diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 70a496a4..67d30d8a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -65,6 +65,10 @@ jobs:
     - name: Install libpng-dev
       run: sudo apt-get install libpng-dev
 
+    - name: Install locale
+      shell: bash
+      run: sudo locale-gen de_DE.UTF-8 && sudo update-locale
+
     - name: Create Build Environment
       run: cmake -E make_directory ${{runner.workspace}}/build
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7f69b7e8..d738f76d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,7 +17,8 @@ add_definitions(-DZINT_VERSION=\"${ZINT_VERSION}\")
 
 option(ZINT_DEBUG     "Set debug compile flags"         OFF)
 option(ZINT_NOOPT     "Set no optimize compile flags"   OFF)
-option(ZINT_SANITIZE  "Set sanitize compile/link flags" OFF)
+option(ZINT_SANITIZE  "Set sanitize address/undefined"  OFF)
+option(ZINT_SANITIZEM "Set sanitize memory (ignored if ZINT_SANITIZE)" OFF)
 option(ZINT_TEST      "Set test compile flag"           OFF)
 option(ZINT_COVERAGE  "Set code coverage flags"         OFF)
 option(ZINT_SHARED    "Build shared library"            ON)
diff --git a/README.linux b/README.linux
index 26ed42cd..c7f7f5e0 100644
--- a/README.linux
+++ b/README.linux
@@ -1,4 +1,4 @@
-% README.linux 2025-02-02
+% README.linux 2025-02-19
 % Tested on Ubuntu 20.04.4 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and
 % Fedora Linux 41 (Workstation Edition)
 
@@ -122,21 +122,26 @@ On Fedora you may have to set LD_LIBRARY_PATH for zint ("libzint.so") and zint-q
 
 A number of options are available:
 
-ZINT_COVERAGE:BOOL=OFF # Set code coverage flags
-ZINT_DEBUG:BOOL=OFF    # Set debug compile flags
-ZINT_FRONTEND:BOOL=ON  # Build frontend
-ZINT_NOOPT:BOOL=OFF    # Set no optimize compile flags
-ZINT_SANITIZE:BOOL=OFF # Set sanitize compile/link flags
-ZINT_SHARED:BOOL=ON    # Build shared library
-ZINT_STATIC:BOOL=OFF   # Build static library
-ZINT_TEST:BOOL=OFF     # Set test compile flag
-ZINT_UNINSTALL:BOOL=ON # Add uninstall target
-ZINT_USE_PNG:BOOL=ON   # Build with PNG support
-ZINT_USE_QT:BOOL=ON    # Build with Qt support
-ZINT_QT6:BOOL=OFF      # If ZINT_USE_QT, use Qt6
+ZINT_COVERAGE:BOOL=OFF  # Set code coverage flags
+ZINT_DEBUG:BOOL=OFF     # Set debug compile flags
+ZINT_FRONTEND:BOOL=ON   # Build frontend
+ZINT_NOOPT:BOOL=OFF     # Set no optimize compile flags
+ZINT_SANITIZE:BOOL=OFF  # Set sanitize compile/link flags
+ZINT_SANITIZE:BOOL=OFF  # Set sanitize address/undefined
+ZINT_SANITIZEM:BOOL=OFF # Set sanitize memory (ignored if ZINT_SANITIZE)
+ZINT_SHARED:BOOL=ON     # Build shared library
+ZINT_STATIC:BOOL=OFF    # Build static library
+ZINT_TEST:BOOL=OFF      # Set test compile flag
+ZINT_UNINSTALL:BOOL=ON  # Add uninstall target
+ZINT_USE_PNG:BOOL=ON    # Build with PNG support
+ZINT_USE_QT:BOOL=ON     # Build with Qt support
+ZINT_QT6:BOOL=OFF       # If ZINT_USE_QT, use Qt6
 
 which can be set by doing e.g.
 
     cmake -DZINT_SANITIZE=ON ..
 
+Note that ZINT_SANITIZEM (Clang only) is incompatible with ZINT_SANITIZE, and also with
+ZINT_USE_PNG, unless libpng has also been instrumented with -fsanitize=memory.
+
 For details on ZINT_TEST and building the zint test suite, see "backend/tests/README".
diff --git a/backend/CMakeLists.txt b/backend/CMakeLists.txt
index eb75db18..45538515 100644
--- a/backend/CMakeLists.txt
+++ b/backend/CMakeLists.txt
@@ -88,6 +88,13 @@ else()
     message(STATUS "Not using PNG")
 endif()
 
+# Incompatible with ZINT_SANITIZE (and also with ZINT_USE_PNG unless libpng instrumented)
+if(NOT ZINT_SANITIZE AND ZINT_SANITIZEM AND CMAKE_C_COMPILER_ID MATCHES "Clang")
+    add_compile_options(-fsanitize=memory -fsanitize-memory-track-origins -fno-omit-frame-pointer -O2)
+    link_libraries(-fsanitize=memory)
+    zint_target_compile_definitions(PRIVATE ZINT_SANITIZEM)
+endif()
+
 if(ZINT_TEST)
     zint_target_compile_definitions(PUBLIC ZINT_TEST)
 endif()
diff --git a/backend/filemem.c b/backend/filemem.c
index 7b752cb6..1f408e87 100644
--- a/backend/filemem.c
+++ b/backend/filemem.c
@@ -108,6 +108,9 @@ INTERNAL int fm_open(struct filemem *restrict const fmp, struct zint_symbol *sym
         if (!(fmp->mem = (unsigned char *) malloc(FM_PAGE_SIZE))) {
             return fm_seterr(fmp, ENOMEM);
         }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+        memset(fmp->mem, 0, FM_PAGE_SIZE);
+#endif
         fmp->memsize = FM_PAGE_SIZE;
         if (symbol->memfile) {
             free(symbol->memfile);
@@ -160,6 +163,9 @@ static int fm_mem_expand(struct filemem *restrict const fmp, const size_t size)
         fm_clear_mem(fmp);
         return fm_seterr(fmp, new_size > 0x40000000 ? EINVAL : ENOMEM);
     }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+    memset(new_mem + fmp->memsize, 0, new_size - fmp->memsize);
+#endif
     fmp->mem = new_mem;
     fmp->memsize = new_size;
     return 1;
diff --git a/backend/gif.c b/backend/gif.c
index ff980c46..d7c3b6e6 100644
--- a/backend/gif.c
+++ b/backend/gif.c
@@ -268,7 +268,7 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, unsigned char *pixelbuf)
     if (State.fOutPaged) {
         State.OutLength = GIF_LZW_PAGE_SIZE;
     }
-    if (!(State.pOut = (unsigned char *) malloc(State.OutLength))) {
+    if (!(State.pOut = (unsigned char *) calloc(1, State.OutLength))) {
         return errtxt(ZINT_ERROR_MEMORY, symbol, 614, "Insufficient memory for GIF LZW buffer");
     }
 
diff --git a/backend/raster.c b/backend/raster.c
index f4aa0817..a225c4c7 100644
--- a/backend/raster.c
+++ b/backend/raster.c
@@ -115,6 +115,9 @@ static int buffer_plot(struct zint_symbol *symbol, const unsigned char *pixelbuf
     if (!(symbol->bitmap = (unsigned char *) raster_malloc(bm_bitmap_size, 0 /*prev_size*/))) {
         return errtxt(ZINT_ERROR_MEMORY, symbol, 661, "Insufficient memory for bitmap buffer");
     }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+    memset(symbol->bitmap, 0, bm_bitmap_size);
+#endif
 
     if (plot_alpha) {
         const size_t alpha_size = (size_t) symbol->bitmap_width * symbol->bitmap_height;
@@ -178,10 +181,11 @@ static int save_raster_image_to_file(struct zint_symbol *symbol, const int image
     }
 
     if (rotate_angle) {
-        if (!(rotated_pixbuf = (unsigned char *) raster_malloc((size_t) image_width * image_height,
-                                                                0 /*prev_size*/))) {
+        size_t image_size = (size_t) image_width * image_height;
+        if (!(rotated_pixbuf = (unsigned char *) raster_malloc((size_t) image_size, 0 /*prev_size*/))) {
             return errtxt(ZINT_ERROR_MEMORY, symbol, 650, "Insufficient memory for pixel buffer");
         }
+        memset(rotated_pixbuf, DEFAULT_PAPER, image_size);
     }
 
     /* Rotate image before plotting */
diff --git a/backend/tests/test_2of5.c b/backend/tests/test_2of5.c
index d32899c4..1a7740a4 100644
--- a/backend/tests/test_2of5.c
+++ b/backend/tests/test_2of5.c
@@ -77,7 +77,7 @@ static void test_large(const testCtx *const p_ctx) {
     int i, length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char data_buf[4096];
+    char data_buf[4096] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStartSymbol("test_large", &symbol);
 
@@ -128,47 +128,47 @@ static void test_hrt(const testCtx *const p_ctx) {
         /*  4*/ { BARCODE_C25STANDARD, 2, -1, "123456789", "123456789" }, /* Suppresses printing of check digit */
         /*  5*/ { BARCODE_C25STANDARD, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" }, /* Unless plain HRT */
         /*  6*/ { BARCODE_C25INTER, -1, -1, "123456789", "0123456789" }, /* Adds leading zero if odd */
-        /*  6*/ { BARCODE_C25INTER, -1, BARCODE_PLAIN_HRT, "123456789", "0123456789" },
-        /*  7*/ { BARCODE_C25INTER, 1, -1, "123456789", "1234567895" }, /* Unless check digit added when it becomes even */
-        /*  8*/ { BARCODE_C25INTER, 1, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
-        /*  9*/ { BARCODE_C25INTER, 2, -1, "123456789", "123456789" },
-        /* 10*/ { BARCODE_C25INTER, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
-        /* 11*/ { BARCODE_C25INTER, -1, -1, "1234567890", "1234567890" }, /* No leading zero if even */
-        /* 12*/ { BARCODE_C25INTER, -1, BARCODE_PLAIN_HRT, "1234567890", "1234567890" },
-        /* 13*/ { BARCODE_C25INTER, 1, -1, "1234567890", "012345678905" }, /* Unless check digit added when it becomes odd */
-        /* 14*/ { BARCODE_C25INTER, 1, BARCODE_PLAIN_HRT, "1234567890", "012345678905" },
-        /* 15*/ { BARCODE_C25INTER, 2, -1, "1234567890", "01234567890" },
-        /* 16*/ { BARCODE_C25INTER, 2, BARCODE_PLAIN_HRT, "1234567890", "012345678905" },
-        /* 17*/ { BARCODE_C25IATA, -1, -1, "123456789", "123456789" },
-        /* 18*/ { BARCODE_C25IATA, -1, BARCODE_PLAIN_HRT, "123456789", "123456789" },
-        /* 19*/ { BARCODE_C25IATA, 1, -1, "123456789", "1234567895" },
-        /* 20*/ { BARCODE_C25IATA, 1, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
-        /* 21*/ { BARCODE_C25IATA, 2, -1, "123456789", "123456789" },
-        /* 22*/ { BARCODE_C25IATA, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
-        /* 23*/ { BARCODE_C25LOGIC, -1, -1, "123456789", "123456789" },
-        /* 24*/ { BARCODE_C25LOGIC, -1, BARCODE_PLAIN_HRT, "123456789", "123456789" },
-        /* 25*/ { BARCODE_C25LOGIC, 1, -1, "123456789", "1234567895" },
-        /* 26*/ { BARCODE_C25LOGIC, 1, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
-        /* 27*/ { BARCODE_C25LOGIC, 2, -1, "123456789", "123456789" },
-        /* 28*/ { BARCODE_C25LOGIC, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
-        /* 29*/ { BARCODE_C25IND, -1, -1, "123456789", "123456789" },
-        /* 30*/ { BARCODE_C25IND, -1, BARCODE_PLAIN_HRT, "123456789", "123456789" },
-        /* 31*/ { BARCODE_C25IND, 1, -1, "123456789", "1234567895" },
-        /* 32*/ { BARCODE_C25IND, 1, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
-        /* 33*/ { BARCODE_C25IND, 2, -1, "123456789", "123456789" },
-        /* 34*/ { BARCODE_C25IND, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
-        /* 35*/ { BARCODE_DPLEIT, -1, -1, "123456789", "00001.234.567.890" }, /* Leading zeroes added to make 13 + appended checksum */
-        /* 36*/ { BARCODE_DPLEIT, -1, BARCODE_PLAIN_HRT, "123456789", "00001234567890" },
-        /* 37*/ { BARCODE_DPLEIT, -1, -1, "1234567890123", "12345.678.901.236" },
-        /* 38*/ { BARCODE_DPLEIT, -1, BARCODE_PLAIN_HRT, "1234567890123", "12345678901236" },
-        /* 39*/ { BARCODE_DPIDENT, -1, -1, "123456789", "00.12 3.456.789 0" }, /* Leading zeroes added to make 11 + appended checksum */
-        /* 40*/ { BARCODE_DPIDENT, -1, BARCODE_PLAIN_HRT, "123456789", "001234567890" },
-        /* 41*/ { BARCODE_DPIDENT, -1, -1, "12345678901", "12.34 5.678.901 6" },
-        /* 42*/ { BARCODE_DPIDENT, -1, BARCODE_PLAIN_HRT, "12345678901", "123456789016" },
-        /* 43*/ { BARCODE_ITF14, -1, -1, "123456789", "00001234567895" }, /* Leading zeroes added to make 13 + appended checksum */
-        /* 44*/ { BARCODE_ITF14, -1, BARCODE_PLAIN_HRT, "123456789", "00001234567895" },
-        /* 45*/ { BARCODE_ITF14, -1, -1, "1234567890123", "12345678901231" },
-        /* 46*/ { BARCODE_ITF14, -1, BARCODE_PLAIN_HRT, "1234567890123", "12345678901231" },
+        /*  7*/ { BARCODE_C25INTER, -1, BARCODE_PLAIN_HRT, "123456789", "0123456789" },
+        /*  8*/ { BARCODE_C25INTER, 1, -1, "123456789", "1234567895" }, /* Unless check digit added when it becomes even */
+        /*  9*/ { BARCODE_C25INTER, 1, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
+        /* 10*/ { BARCODE_C25INTER, 2, -1, "123456789", "123456789" },
+        /* 11*/ { BARCODE_C25INTER, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
+        /* 12*/ { BARCODE_C25INTER, -1, -1, "1234567890", "1234567890" }, /* No leading zero if even */
+        /* 13*/ { BARCODE_C25INTER, -1, BARCODE_PLAIN_HRT, "1234567890", "1234567890" },
+        /* 14*/ { BARCODE_C25INTER, 1, -1, "1234567890", "012345678905" }, /* Unless check digit added when it becomes odd */
+        /* 15*/ { BARCODE_C25INTER, 1, BARCODE_PLAIN_HRT, "1234567890", "012345678905" },
+        /* 16*/ { BARCODE_C25INTER, 2, -1, "1234567890", "01234567890" },
+        /* 17*/ { BARCODE_C25INTER, 2, BARCODE_PLAIN_HRT, "1234567890", "012345678905" },
+        /* 18*/ { BARCODE_C25IATA, -1, -1, "123456789", "123456789" },
+        /* 19*/ { BARCODE_C25IATA, -1, BARCODE_PLAIN_HRT, "123456789", "123456789" },
+        /* 20*/ { BARCODE_C25IATA, 1, -1, "123456789", "1234567895" },
+        /* 21*/ { BARCODE_C25IATA, 1, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
+        /* 22*/ { BARCODE_C25IATA, 2, -1, "123456789", "123456789" },
+        /* 23*/ { BARCODE_C25IATA, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
+        /* 24*/ { BARCODE_C25LOGIC, -1, -1, "123456789", "123456789" },
+        /* 25*/ { BARCODE_C25LOGIC, -1, BARCODE_PLAIN_HRT, "123456789", "123456789" },
+        /* 26*/ { BARCODE_C25LOGIC, 1, -1, "123456789", "1234567895" },
+        /* 27*/ { BARCODE_C25LOGIC, 1, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
+        /* 28*/ { BARCODE_C25LOGIC, 2, -1, "123456789", "123456789" },
+        /* 29*/ { BARCODE_C25LOGIC, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
+        /* 30*/ { BARCODE_C25IND, -1, -1, "123456789", "123456789" },
+        /* 31*/ { BARCODE_C25IND, -1, BARCODE_PLAIN_HRT, "123456789", "123456789" },
+        /* 32*/ { BARCODE_C25IND, 1, -1, "123456789", "1234567895" },
+        /* 33*/ { BARCODE_C25IND, 1, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
+        /* 34*/ { BARCODE_C25IND, 2, -1, "123456789", "123456789" },
+        /* 35*/ { BARCODE_C25IND, 2, BARCODE_PLAIN_HRT, "123456789", "1234567895" },
+        /* 36*/ { BARCODE_DPLEIT, -1, -1, "123456789", "00001.234.567.890" }, /* Leading zeroes added to make 13 + appended checksum */
+        /* 37*/ { BARCODE_DPLEIT, -1, BARCODE_PLAIN_HRT, "123456789", "00001234567890" },
+        /* 38*/ { BARCODE_DPLEIT, -1, -1, "1234567890123", "12345.678.901.236" },
+        /* 39*/ { BARCODE_DPLEIT, -1, BARCODE_PLAIN_HRT, "1234567890123", "12345678901236" },
+        /* 40*/ { BARCODE_DPIDENT, -1, -1, "123456789", "00.12 3.456.789 0" }, /* Leading zeroes added to make 11 + appended checksum */
+        /* 41*/ { BARCODE_DPIDENT, -1, BARCODE_PLAIN_HRT, "123456789", "001234567890" },
+        /* 42*/ { BARCODE_DPIDENT, -1, -1, "12345678901", "12.34 5.678.901 6" },
+        /* 43*/ { BARCODE_DPIDENT, -1, BARCODE_PLAIN_HRT, "12345678901", "123456789016" },
+        /* 44*/ { BARCODE_ITF14, -1, -1, "123456789", "00001234567895" }, /* Leading zeroes added to make 13 + appended checksum */
+        /* 45*/ { BARCODE_ITF14, -1, BARCODE_PLAIN_HRT, "123456789", "00001234567895" },
+        /* 46*/ { BARCODE_ITF14, -1, -1, "1234567890123", "12345678901231" },
+        /* 47*/ { BARCODE_ITF14, -1, BARCODE_PLAIN_HRT, "1234567890123", "12345678901231" },
     };
     const int data_size = ARRAY_SIZE(data);
     int i, length, ret;
diff --git a/backend/tests/test_big5.c b/backend/tests/test_big5.c
index 5cd0289c..b3ebe83e 100644
--- a/backend/tests/test_big5.c
+++ b/backend/tests/test_big5.c
@@ -43,7 +43,7 @@ INTERNAL int u_big5_test(const unsigned int u, unsigned char *dest);
 
 /* Version of `u_big5()` taking unsigned int destination for backward-compatible testing */
 static int u_big5_int(unsigned int u, unsigned int *d) {
-    unsigned char dest[2];
+    unsigned char dest[2] = {0}; /* Suppress clang -fsanitize=memory false positive */
     int ret = u_big5_test(u, dest);
     if (ret) {
         *d = ret == 1 ? dest[0] : ((dest[0] << 8) | dest[1]);
@@ -157,6 +157,8 @@ static int big5_utf8(struct zint_symbol *symbol, const unsigned char source[], i
     unsigned int i, length;
     unsigned int *utfdata = (unsigned int *) z_alloca(sizeof(unsigned int) * (*p_length + 1));
 
+    memset(utfdata, 0, sizeof(unsigned int) * (*p_length + 1)); /* Suppress clang -fsanitize=memory false positive */
+
     error_number = utf8_to_unicode(symbol, source, utfdata, p_length, 0 /*disallow_4byte*/);
     if (error_number != 0) {
         return error_number;
diff --git a/backend/tests/test_bmp.c b/backend/tests/test_bmp.c
index e45bd4d9..1515cc62 100644
--- a/backend/tests/test_bmp.c
+++ b/backend/tests/test_bmp.c
@@ -155,7 +155,7 @@ static void test_print(const testCtx *const p_ctx) {
     char expected_file[4096];
     char escaped[1024];
     int escaped_size = 1024;
-    unsigned char filebuf[32768];
+    unsigned char filebuf[32768] = {0}; /* Suppress clang -fsanitize=memory false positive */
     int filebuf_size;
 
     const char *const have_identify = testUtilHaveIdentify();
diff --git a/backend/tests/test_code11.c b/backend/tests/test_code11.c
index f74c467c..0791cc6b 100644
--- a/backend/tests/test_code11.c
+++ b/backend/tests/test_code11.c
@@ -55,7 +55,7 @@ static void test_large(const testCtx *const p_ctx) {
     int i, length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char data_buf[4096];
+    char data_buf[4096] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStartSymbol("test_large", &symbol);
 
diff --git a/backend/tests/test_code128.c b/backend/tests/test_code128.c
index 34a71984..4143103b 100644
--- a/backend/tests/test_code128.c
+++ b/backend/tests/test_code128.c
@@ -103,7 +103,7 @@ static void test_large(const testCtx *const p_ctx) {
     char escaped2[1024];
     char cmp_buf[8192];
     char cmp_msg[1024];
-    char ret_buf[8192];
+    char ret_buf[8192] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
     int do_zxingcpp = (debug & ZINT_DEBUG_TEST_ZXINGCPP) && testUtilHaveZXingCPPDecoder(); /* Only do ZXing-C++ test if asked, too slow otherwise */
diff --git a/backend/tests/test_common.c b/backend/tests/test_common.c
index cac8f5e5..575edcc9 100644
--- a/backend/tests/test_common.c
+++ b/backend/tests/test_common.c
@@ -342,7 +342,7 @@ static void test_not_sane_lookup(const testCtx *const p_ctx) {
     const int data_size = ARRAY_SIZE(data);
     int i, length, ret;
     int test_length;
-    int posns[32];
+    int posns[32] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_not_sane_lookup");
 
@@ -666,7 +666,7 @@ static void test_utf8_to_unicode(const testCtx *const p_ctx) {
     const int data_size = ARRAY_SIZE(data);
     int i, length, ret;
 
-    unsigned int vals[20];
+    unsigned int vals[20] = {0}; /* Suppress clang -fsanitize=memory false positive */
     struct zint_symbol s_symbol;
     struct zint_symbol *symbol = &s_symbol;
 
diff --git a/backend/tests/test_composite.c b/backend/tests/test_composite.c
index d5781100..707c278f 100644
--- a/backend/tests/test_composite.c
+++ b/backend/tests/test_composite.c
@@ -1534,7 +1534,7 @@ static void test_examples(const testCtx *const p_ctx) {
     char escaped[1024];
     char esc_composite[4096];
 
-    char bwipp_buf[32768];
+    char bwipp_buf[32768] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char bwipp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
@@ -1836,7 +1836,7 @@ static void test_ean128_cc_shift(const testCtx *const p_ctx) {
     int i, length, composite_length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char bwipp_buf[8192];
+    char bwipp_buf[8192] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char bwipp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
@@ -2384,7 +2384,7 @@ static void test_encodation_0(const testCtx *const p_ctx) {
     int i, length, composite_length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char bwipp_buf[8192];
+    char bwipp_buf[8192] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char bwipp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
@@ -2522,7 +2522,7 @@ static void test_encodation_10(const testCtx *const p_ctx) {
     int i, length, composite_length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char bwipp_buf[8192];
+    char bwipp_buf[8192] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char bwipp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
@@ -2938,7 +2938,7 @@ static void test_encodation_11(const testCtx *const p_ctx) {
     int i, length, composite_length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char bwipp_buf[8192];
+    char bwipp_buf[8192] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char bwipp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
@@ -3089,7 +3089,7 @@ static void test_addongap(const testCtx *const p_ctx) {
     int i, length, composite_length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char bwipp_buf[8192];
+    char bwipp_buf[8192] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char bwipp_msg[1024];
 
     const char *composite = "[91]12";
diff --git a/backend/tests/test_eci.c b/backend/tests/test_eci.c
index 0fbe6241..a852c08f 100644
--- a/backend/tests/test_eci.c
+++ b/backend/tests/test_eci.c
@@ -758,7 +758,7 @@ static void test_utf8_to_eci_ascii(const testCtx *const p_ctx) {
     int data_size = ARRAY_SIZE(data);
     int i, length, ret;
 
-    char dest[128];
+    char dest[128] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_utf8_to_eci_ascii");
 
@@ -815,7 +815,7 @@ static void test_utf8_to_eci_utf16be(const testCtx *const p_ctx) {
 
     for (i = 0; i < data_size; i++) {
         int out_length, eci_length;
-        char dest[1024];
+        char dest[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
         if (testContinue(p_ctx, i)) continue;
 
@@ -880,7 +880,7 @@ static void test_utf8_to_eci_utf16le(const testCtx *const p_ctx) {
 
     for (i = 0; i < data_size; i++) {
         int out_length, eci_length;
-        char dest[1024];
+        char dest[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
         if (testContinue(p_ctx, i)) continue;
 
@@ -942,7 +942,7 @@ static void test_utf8_to_eci_utf32be(const testCtx *const p_ctx) {
 
     for (i = 0; i < data_size; i++) {
         int out_length, eci_length;
-        char dest[1024];
+        char dest[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
         if (testContinue(p_ctx, i)) continue;
 
@@ -1006,7 +1006,7 @@ static void test_utf8_to_eci_utf32le(const testCtx *const p_ctx) {
 
     for (i = 0; i < data_size; i++) {
         int out_length, eci_length;
-        char dest[1024];
+        char dest[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
         if (testContinue(p_ctx, i)) continue;
 
diff --git a/backend/tests/test_filemem.c b/backend/tests/test_filemem.c
index 40f2c766..53e4ab0f 100644
--- a/backend/tests/test_filemem.c
+++ b/backend/tests/test_filemem.c
@@ -96,7 +96,7 @@ static void test_svg(const testCtx *const p_ctx) {
 
             assert_equal(symbol->memfile_size, expected_size, "i:%d memfile_size %d != %d (%s)\n",
                             i, symbol->memfile_size, expected_size, symbol->errtxt);
-            ret = memcmp(symbol->memfile, data[i].expected, symbol->memfile_size);
+            ret = memcmp(symbol->memfile, data[i].expected, expected_size);
             assert_zero(ret, "i:%d memcmp() %d != 0\n", i, ret);
         } else {
             assert_null(symbol->memfile, "i:%d memfile != NULL (%s)\n", i, symbol->errtxt);
@@ -147,7 +147,7 @@ static void test_putsf(const testCtx *const p_ctx) {
 
     struct zint_symbol symbol_data = {0};
     struct zint_symbol *const symbol = &symbol_data;
-    struct filemem fm;
+    struct filemem fm = {0}; /* Suppress clang -fsanitize=memory false positive */
     struct filemem *const fmp = &fm;
 #ifndef ZINT_TEST_NO_FMEMOPEN
     FILE *fp;
@@ -338,7 +338,7 @@ static void test_seek(const testCtx *const p_ctx) {
     int j;
     struct zint_symbol symbol_data = {0};
     struct zint_symbol *const symbol = &symbol_data;
-    struct filemem fm;
+    struct filemem fm = {0}; /* Suppress clang -fsanitize=memory false positive */
     struct filemem *const fmp = &fm;
     const char outfile[] = "test_seek.tst";
 
diff --git a/backend/tests/test_gb18030.c b/backend/tests/test_gb18030.c
index 453116bd..1c8ee1e3 100644
--- a/backend/tests/test_gb18030.c
+++ b/backend/tests/test_gb18030.c
@@ -282,7 +282,7 @@ static void test_gb18030_utf8(const testCtx *const p_ctx) {
     int i, length, ret;
 
     struct zint_symbol symbol = {0};
-    unsigned int gbdata[30];
+    unsigned int gbdata[30] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_gb18030_utf8");
 
@@ -399,7 +399,7 @@ static void test_gb18030_utf8_to_eci(const testCtx *const p_ctx) {
     int data_size = ARRAY_SIZE(data);
     int i, length, ret;
 
-    unsigned int gbdata[30];
+    unsigned int gbdata[30] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_gb18030_utf8_to_eci");
 
@@ -455,7 +455,7 @@ static void test_gb18030_cpy(const testCtx *const p_ctx) {
     int data_size = ARRAY_SIZE(data);
     int i, length;
 
-    unsigned int gbdata[30];
+    unsigned int gbdata[30] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_gb18030_cpy");
 
diff --git a/backend/tests/test_gb2312.c b/backend/tests/test_gb2312.c
index b96793aa..a2838354 100644
--- a/backend/tests/test_gb2312.c
+++ b/backend/tests/test_gb2312.c
@@ -188,7 +188,7 @@ static void test_gb2312_utf8(const testCtx *const p_ctx) {
     int i, length, ret;
 
     struct zint_symbol symbol = {0};
-    unsigned int gbdata[20];
+    unsigned int gbdata[20] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_gb2312_utf8");
 
@@ -290,7 +290,7 @@ static void test_gb2312_utf8_to_eci(const testCtx *const p_ctx) {
     int data_size = ARRAY_SIZE(data);
     int i, length, ret;
 
-    unsigned int gbdata[20];
+    unsigned int gbdata[20] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_gb2312_utf8_to_eci");
 
@@ -346,7 +346,7 @@ static void test_gb2312_cpy(const testCtx *const p_ctx) {
     int data_size = ARRAY_SIZE(data);
     int i, length;
 
-    unsigned int gbdata[20];
+    unsigned int gbdata[20] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_gb2312_cpy");
 
diff --git a/backend/tests/test_gs1.c b/backend/tests/test_gs1.c
index f8ef9a45..7ad8b9e6 100644
--- a/backend/tests/test_gs1.c
+++ b/backend/tests/test_gs1.c
@@ -1446,9 +1446,9 @@ static void test_gs1_verify(const testCtx *const p_ctx) {
     const int data_size = ARRAY_SIZE(data);
     int i, length, ret;
     struct zint_symbol *symbol = NULL;
-    int reduced_length;
+    int reduced_length = 0; /* Suppress clang -fsanitize=memory false positive */
 
-    char reduced[1024];
+    char reduced[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char escaped[1024];
 
     testStartSymbol("test_gs1_verify", &symbol);
@@ -2154,9 +2154,9 @@ static void test_gs1_lint(const testCtx *const p_ctx) {
     const int data_size = ARRAY_SIZE(data);
     int i, length, ret;
     struct zint_symbol *symbol = NULL;
-    int reduced_length;
+    int reduced_length = 0; /* Suppress clang -fsanitize=memory false positive */
 
-    char reduced[1024];
+    char reduced[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStartSymbol("test_gs1_lint", &symbol);
 
diff --git a/backend/tests/test_hanxin.c b/backend/tests/test_hanxin.c
index 3817c130..2d97d612 100644
--- a/backend/tests/test_hanxin.c
+++ b/backend/tests/test_hanxin.c
@@ -3452,7 +3452,7 @@ static void test_encode_segs(const testCtx *const p_ctx) {
     int i, j, seg_count, ret;
     struct zint_symbol *symbol = NULL;
 
-    char escaped[8192];
+    char escaped[8192] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_buf[32768];
     char cmp_msg[1024];
 
diff --git a/backend/tests/test_imail.c b/backend/tests/test_imail.c
index 8eed57f1..9c959051 100644
--- a/backend/tests/test_imail.c
+++ b/backend/tests/test_imail.c
@@ -239,7 +239,7 @@ static void test_input(const testCtx *const p_ctx) {
     int i, length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char cmp_buf[8192];
+    char cmp_buf[8192] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
diff --git a/backend/tests/test_ksx1001.c b/backend/tests/test_ksx1001.c
index f8a55656..05ec8298 100644
--- a/backend/tests/test_ksx1001.c
+++ b/backend/tests/test_ksx1001.c
@@ -44,7 +44,7 @@ INTERNAL int u_ksx1001_test(const unsigned int u, unsigned char *dest);
 
 /* Version of `u_ksx1001()` taking unsigned int destination for backward-compatible testing */
 static int u_ksx1001_int(const unsigned int u, unsigned int *d) {
-    unsigned char dest[2];
+    unsigned char dest[2] = {0}; /* Suppress clang -fsanitize=memory false positive */
     int ret = u_ksx1001_test(u, dest);
     if (ret) {
         *d = ret == 1 ? dest[0] : ((dest[0] << 8) | dest[1]);
diff --git a/backend/tests/test_library.c b/backend/tests/test_library.c
index 8abb6fe2..decd300b 100644
--- a/backend/tests/test_library.c
+++ b/backend/tests/test_library.c
@@ -1577,7 +1577,7 @@ static int test_prev_ZBarcode_BarcodeName(int symbol_id, char name[32]) {
 static void test_barcode_name(const testCtx *const p_ctx) {
 
     int ret;
-    char name[32];
+    char name[32] = {0}; /* Suppress clang -fsanitize=memory false positive */
     int symbol_id;
 
     (void)p_ctx;
diff --git a/backend/tests/test_maxicode.c b/backend/tests/test_maxicode.c
index ac21c23a..4571e3b4 100644
--- a/backend/tests/test_maxicode.c
+++ b/backend/tests/test_maxicode.c
@@ -255,7 +255,7 @@ static void test_input(const testCtx *const p_ctx) {
     struct zint_symbol *symbol = NULL;
 
     char escaped[1024];
-    char cmp_buf[32768];
+    char cmp_buf[32768] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
diff --git a/backend/tests/test_output.c b/backend/tests/test_output.c
index d81158fb..3ffdf187 100644
--- a/backend/tests/test_output.c
+++ b/backend/tests/test_output.c
@@ -68,7 +68,7 @@ static void test_check_colour_options(const testCtx *const p_ctx) {
     };
     const int data_size = ARRAY_SIZE(data);
     int i, ret;
-    struct zint_symbol symbol;
+    struct zint_symbol symbol = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_check_colour_options");
 
@@ -121,7 +121,7 @@ static void test_colour_get_rgb(const testCtx *const p_ctx) {
     for (i = 0; i < data_size; i++) {
         /* Suppress clang-16 run-time exception MemorySanitizer: use-of-uninitialized-value (fixed in clang-17) */
         unsigned char red = 0, green = 0, blue = 0, alpha = 0, rgb_alpha = 0;
-        int cyan, magenta, yellow, black;
+        int cyan = 0, magenta = 0, yellow = 0, black = 0; /* Suppress clang -fsanitize=memory false positive */
         int have_alpha;
         char rgb[64];
         char cmyk[64];
@@ -179,8 +179,9 @@ static void test_colour_get_cmyk(const testCtx *const p_ctx) {
     testStart("test_colour_get_cmyk");
 
     for (i = 0; i < data_size; i++) {
-        int cyan, magenta, yellow, black;
-        unsigned char red, green, blue, alpha, rgb_alpha;
+        /* Suppress clang -fsanitize=memory false positives */
+        int cyan = 0, magenta = 0, yellow = 0, black = 0;
+        unsigned char red = '\0', green = '\0', blue = '\0', alpha = '\0', rgb_alpha = '\0';
         char rgb[16];
 
         if (testContinue(p_ctx, i)) continue;
diff --git a/backend/tests/test_pdf417.c b/backend/tests/test_pdf417.c
index 89a4752b..fd441ae4 100644
--- a/backend/tests/test_pdf417.c
+++ b/backend/tests/test_pdf417.c
@@ -5762,7 +5762,7 @@ static void test_numbprocess(const testCtx *const p_ctx) {
     const int data_size = ARRAY_SIZE(data);
     int i, length;
 
-    short chainemc[32];
+    short chainemc[32] = {0}; /* Suppress clang -fsanitize=memory false positive */
     int mclength;
 
     testStart("test_numbprocess");
diff --git a/backend/tests/test_plessey.c b/backend/tests/test_plessey.c
index 866873ea..00042173 100644
--- a/backend/tests/test_plessey.c
+++ b/backend/tests/test_plessey.c
@@ -71,7 +71,7 @@ static void test_large(const testCtx *const p_ctx) {
     int i, length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char data_buf[4096];
+    char data_buf[4096] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStartSymbol("test_large", &symbol);
 
diff --git a/backend/tests/test_postal.c b/backend/tests/test_postal.c
index b7579566..cc76711f 100644
--- a/backend/tests/test_postal.c
+++ b/backend/tests/test_postal.c
@@ -82,7 +82,7 @@ static void test_large(const testCtx *const p_ctx) {
     int i, length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char data_buf[4096];
+    char data_buf[4096] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStartSymbol("test_large", &symbol);
 
diff --git a/backend/tests/test_ps.c b/backend/tests/test_ps.c
index c3c81920..47f7f2d4 100644
--- a/backend/tests/test_ps.c
+++ b/backend/tests/test_ps.c
@@ -235,7 +235,7 @@ static void test_ps_convert(const testCtx *const p_ctx) {
     const int data_size = ARRAY_SIZE(data);
     int i;
 
-    unsigned char converted[256];
+    unsigned char converted[256] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_ps_convert");
 
diff --git a/backend/tests/test_qr.c b/backend/tests/test_qr.c
index ae4e218e..a997b2d2 100644
--- a/backend/tests/test_qr.c
+++ b/backend/tests/test_qr.c
@@ -72,8 +72,8 @@ static void test_qr_large(const testCtx *const p_ctx) {
 
     char data_buf[ZINT_MAX_DATA_LEN];
 
-    char escaped[ZINT_MAX_DATA_LEN];
-    char cmp_buf[177 * 177 + 1];
+    char escaped[ZINT_MAX_DATA_LEN] = {0}; /* Suppress clang -fsanitize=memory false positive */
+    char cmp_buf[177 * 177 + 1] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
@@ -433,7 +433,7 @@ static void test_qr_input(const testCtx *const p_ctx) {
     struct zint_symbol *symbol = NULL;
 
     char escaped[4096];
-    char cmp_buf[32768];
+    char cmp_buf[32768] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
@@ -763,7 +763,7 @@ static void test_qr_optimize(const testCtx *const p_ctx) {
     struct zint_symbol *symbol = NULL;
 
     char escaped[4096];
-    char cmp_buf[32768];
+    char cmp_buf[32768] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
@@ -8874,7 +8874,7 @@ static void test_rmqr_encode_segs(const testCtx *const p_ctx) {
     struct zint_symbol *symbol = NULL;
 
     char escaped[4096];
-    char cmp_buf[32768];
+    char cmp_buf[32768] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
diff --git a/backend/tests/test_reedsol.c b/backend/tests/test_reedsol.c
index ed7b1dc9..79421745 100644
--- a/backend/tests/test_reedsol.c
+++ b/backend/tests/test_reedsol.c
@@ -1,6 +1,6 @@
 /*
     libzint - the open source barcode library
-    Copyright (C) 2020-2022 Robin Stuart <rstuart114@gmail.com>
+    Copyright (C) 2020-2025 Robin Stuart <rstuart114@gmail.com>
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -263,7 +263,7 @@ static void test_uint_encoding(const testCtx *const p_ctx) {
 
     for (i = 0; i < data_size; i++) {
         int j;
-        rs_uint_t rs_uint;
+        rs_uint_t rs_uint = {0}; /* Suppress clang -fsanitize=memory false positive */
         unsigned int res[1024];
 
         if (testContinue(p_ctx, i)) continue;
diff --git a/backend/tests/test_rss.c b/backend/tests/test_rss.c
index dda5a344..fb99f370 100644
--- a/backend/tests/test_rss.c
+++ b/backend/tests/test_rss.c
@@ -865,7 +865,7 @@ static void test_examples(const testCtx *const p_ctx) {
     int i, length, ret;
     struct zint_symbol *symbol = NULL;
 
-    char escaped[4096];
+    char escaped[4096] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_buf[16384];
     char cmp_msg[1024];
 
diff --git a/backend/tests/test_sjis.c b/backend/tests/test_sjis.c
index 08422a6d..59b6ed74 100644
--- a/backend/tests/test_sjis.c
+++ b/backend/tests/test_sjis.c
@@ -210,7 +210,7 @@ static void test_sjis_utf8(const testCtx *const p_ctx) {
     int i, length, ret;
 
     struct zint_symbol symbol = {0};
-    unsigned int jisdata[20];
+    unsigned int jisdata[20] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_sjis_utf8");
 
@@ -302,7 +302,7 @@ static void test_sjis_utf8_to_eci(const testCtx *const p_ctx) {
     int data_size = ARRAY_SIZE(data);
     int i, length, ret;
 
-    unsigned int jisdata[20];
+    unsigned int jisdata[20] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_sjis_utf8_to_eci");
 
@@ -354,7 +354,7 @@ static void test_sjis_cpy(const testCtx *const p_ctx) {
     int data_size = ARRAY_SIZE(data);
     int i, length;
 
-    unsigned int jisdata[20];
+    unsigned int jisdata[20] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStart("test_sjis_cpy");
 
diff --git a/backend/tests/test_upcean.c b/backend/tests/test_upcean.c
index a67b1218..8884b2c2 100644
--- a/backend/tests/test_upcean.c
+++ b/backend/tests/test_upcean.c
@@ -99,8 +99,8 @@ static void test_upce_input(const testCtx *const p_ctx) {
     struct zint_symbol *symbol = NULL;
 
     char escaped[4096];
-    char cmp_buf[4096];
-    char cmp_msg[1024];
+    char cmp_buf[4096] = {0}; /* Suppress clang -fsanitize=memory false positive */
+    char cmp_msg[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
     int do_zxingcpp = (debug & ZINT_DEBUG_TEST_ZXINGCPP) && testUtilHaveZXingCPPDecoder(); /* Only do ZXing-C++ test if asked, too slow otherwise */
@@ -834,7 +834,7 @@ static void test_vector_same(const testCtx *const p_ctx) {
         }
 
         for (j = 0; j < vectors_size; j++) {
-            struct zint_symbol symbol_vector;
+            struct zint_symbol symbol_vector = {0}; /* Suppress clang -fsanitize=memory false positive */
             symbol_vector.vector = vectors[j];
             vector_free(&symbol_vector);
         }
@@ -974,7 +974,7 @@ static void test_encode(const testCtx *const p_ctx) {
     struct zint_symbol *symbol = NULL;
 
     char escaped[4096];
-    char cmp_buf[4096];
+    char cmp_buf[4096] = {0}; /* Suppress clang -fsanitize=memory false positive */
     char cmp_msg[1024];
 
     int do_bwipp = (debug & ZINT_DEBUG_TEST_BWIPP) && testUtilHaveGhostscript(); /* Only do BWIPP test if asked, too slow otherwise */
diff --git a/backend/tests/test_vector.c b/backend/tests/test_vector.c
index 3f6c4ca3..458536be 100644
--- a/backend/tests/test_vector.c
+++ b/backend/tests/test_vector.c
@@ -689,7 +689,7 @@ static void test_buffer_vector(const testCtx *const p_ctx) {
     struct zint_symbol *symbol = NULL;
 
     const char *text;
-    char errmsg[128];
+    char errmsg[128] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStartSymbol("test_buffer_vector", &symbol);
 
@@ -858,7 +858,7 @@ static void test_has_hrt(const testCtx *const p_ctx) {
     struct zint_symbol *symbol = NULL;
 
     const char *text;
-    char errmsg[128];
+    char errmsg[128] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     testStartSymbol("test_has_hrt", &symbol);
 
diff --git a/backend/tests/testcommon.c b/backend/tests/testcommon.c
index ade4562c..474dd29e 100644
--- a/backend/tests/testcommon.c
+++ b/backend/tests/testcommon.c
@@ -1869,8 +1869,8 @@ int testUtilCmpTxts(const char *txt1, const char *txt2) {
     int ret = -1;
     FILE *fp1;
     FILE *fp2;
-    char buf1[1024];
-    char buf2[1024];
+    char buf1[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
+    char buf2[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
     size_t len1 = 0, len2 = 0;
 
     fp1 = testUtilOpen(txt1, "r");
@@ -1920,8 +1920,8 @@ int testUtilCmpBins(const char *bin1, const char *bin2) {
     int ret = -1;
     FILE *fp1;
     FILE *fp2;
-    char buf1[1024];
-    char buf2[1024];
+    char buf1[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
+    char buf2[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
     size_t len1 = 0, len2 = 0;
 
     fp1 = testUtilOpen(bin1, "rb");
@@ -1970,8 +1970,8 @@ int testUtilCmpEpss(const char *eps1, const char *eps2) {
     int ret = -1;
     FILE *fp1;
     FILE *fp2;
-    char buf1[1024];
-    char buf2[1024];
+    char buf1[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
+    char buf2[1024] = {0}; /* Suppress clang -fsanitize=memory false positive */
     size_t len1 = 0, len2 = 0;
     static char first_line[] = "%!PS-Adobe-3.0 EPSF-3.0\n";
     static char second_line_start[] = "%%Creator: Zint ";
@@ -2053,7 +2053,7 @@ const char *testUtilHaveIdentify(void) {
 
 /* Check raster files */
 int testUtilVerifyIdentify(const char *const prog, const char *filename, int debug) {
-    char cmd[512 + 128];
+    char cmd[512 + 128] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     if (strlen(filename) > 512) {
         return -1;
@@ -2210,7 +2210,7 @@ int testUtilHaveTiffInfo(void) {
 
 /* Check TIF files */
 int testUtilVerifyTiffInfo(const char *filename, int debug) {
-    char cmd[512 + 128];
+    char cmd[512 + 128] = {0}; /* Suppress clang -fsanitize=memory false positive */
 
     if (strlen(filename) > 512) {
         return -1;
diff --git a/backend/vector.c b/backend/vector.c
index b06e94a1..a4c0ec39 100644
--- a/backend/vector.c
+++ b/backend/vector.c
@@ -48,6 +48,9 @@ static int vector_add_rect(struct zint_symbol *symbol, const float x, const floa
         errtxt(0, symbol, 691, "Insufficient memory for vector rectangle");
         return 0;
     }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+    memset(rect, 0, sizeof(struct zint_vector_rect));
+#endif
 
     rect->next = NULL;
     rect->x = x;
@@ -73,6 +76,9 @@ static int vector_add_hexagon(struct zint_symbol *symbol, const float x, const f
     if (!(hexagon = (struct zint_vector_hexagon *) malloc(sizeof(struct zint_vector_hexagon)))) {
         return errtxt(0, symbol, 692, "Insufficient memory for vector hexagon");
     }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+    memset(hexagon, 0, sizeof(struct zint_vector_hexagon));
+#endif
     hexagon->next = NULL;
     hexagon->x = x;
     hexagon->y = y;
@@ -96,6 +102,9 @@ static int vector_add_circle(struct zint_symbol *symbol, const float x, const fl
     if (!(circle = (struct zint_vector_circle *) malloc(sizeof(struct zint_vector_circle)))) {
         return errtxt(0, symbol, 693, "Insufficient memory for vector circle");
     }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+    memset(circle, 0, sizeof(struct zint_vector_circle));
+#endif
     circle->next = NULL;
     circle->x = x;
     circle->y = y;
@@ -121,6 +130,9 @@ static int vector_add_string(struct zint_symbol *symbol, const unsigned char *te
     if (!(string = (struct zint_vector_string *) malloc(sizeof(struct zint_vector_string)))) {
         return errtxt(0, symbol, 694, "Insufficient memory for vector string");
     }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+    memset(string, 0, sizeof(struct zint_vector_string));
+#endif
     string->next = NULL;
     string->x = x;
     string->y = y;
@@ -133,6 +145,9 @@ static int vector_add_string(struct zint_symbol *symbol, const unsigned char *te
         free(string);
         return errtxt(0, symbol, 695, "Insufficient memory for vector string text");
     }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+    memset(string->text, 0, string->length + 1);
+#endif
     memcpy(string->text, text, string->length);
     string->text[string->length] = '\0';
 
@@ -444,6 +459,9 @@ INTERNAL int plot_vector(struct zint_symbol *symbol, int rotate_angle, int file_
     if (!(vector = symbol->vector = (struct zint_vector *) malloc(sizeof(struct zint_vector)))) {
         return errtxt(ZINT_ERROR_MEMORY, symbol, 696, "Insufficient memory for vector header");
     }
+#ifdef ZINT_SANITIZEM /* Suppress clang -fsanitize=memory false positive */
+    memset(vector, 0, sizeof(struct zint_vector));
+#endif
     vector->rectangles = NULL;
     vector->hexagons = NULL;
     vector->circles = NULL;
diff --git a/backend_qt/qzint.h b/backend_qt/qzint.h
index 9ef6c3ea..f4749530 100644
--- a/backend_qt/qzint.h
+++ b/backend_qt/qzint.h
@@ -1,7 +1,7 @@
 /***************************************************************************
  *   Copyright (C) 2008 by BogDan Vatra                                    *
  *   bogdan@licentia.eu                                                    *
- *   Copyright (C) 2010-2023 Robin Stuart                                  *
+ *   Copyright (C) 2010-2025 Robin Stuart                                  *
  *                                                                         *
  *   This program is free software: you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
@@ -107,7 +107,7 @@ public:
 
     /* Dotty mode */
     bool dotty() const; // `symbol->input_mode | BARCODE_DOTTY_MODE`
-    void setDotty(bool botty);
+    void setDotty(bool dotty);
 
     /* Size of dots used in BARCODE_DOTTY_MODE */
     float dotSize() const; // `symbol->dot_size`