diff --git a/apps/shared/avifjpeg.c b/apps/shared/avifjpeg.c
index 98cfbc3b6e..0ff015769f 100644
--- a/apps/shared/avifjpeg.c
+++ b/apps/shared/avifjpeg.c
@@ -22,6 +22,18 @@
 #include <libxml/parser.h>
 #endif
 
+#if defined(__clang__) && defined(__has_feature)
+#if __has_feature(memory_sanitizer)
+#include <sanitizer/msan_interface.h>
+#define AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) __msan_unpoison(address, size)
+#endif
+#endif
+#if !defined(AVIF_ANNOTATE_MEMORY_IS_INITIALIZED)
+#define AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
+    do {                                                   \
+    } while (0)
+#endif
+
 #define AVIF_MIN(a, b) (((a) < (b)) ? (a) : (b))
 #define AVIF_MAX(a, b) (((a) > (b)) ? (a) : (b))
 
@@ -977,8 +989,11 @@ static avifBool avifJPEGReadInternal(FILE * f,
 
         int row = 0;
         while (cinfo.output_scanline < cinfo.output_height) {
-            jpeg_read_scanlines(&cinfo, buffer, 1);
+            if (jpeg_read_scanlines(&cinfo, buffer, 1) < 1) {
+                goto cleanup;
+            }
             uint8_t * pixelRow = &rgb.pixels[row * rgb.rowBytes];
+            AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(buffer[0], rgb.rowBytes);
             memcpy(pixelRow, buffer[0], rgb.rowBytes);
             ++row;
         }
@@ -1344,10 +1359,12 @@ avifBool avifJPEGWrite(const char * outputFilename, const avifImage * avif, int
 
         avifROData remainingExif = { exif.data, exif.size };
         while (remainingExif.size > AVIF_JPEG_MAX_MARKER_DATA_LENGTH) {
+            AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(remainingExif.data, AVIF_JPEG_MAX_MARKER_DATA_LENGTH);
             jpeg_write_marker(&cinfo, JPEG_APP0 + 1, remainingExif.data, AVIF_JPEG_MAX_MARKER_DATA_LENGTH);
             remainingExif.data += AVIF_JPEG_MAX_MARKER_DATA_LENGTH;
             remainingExif.size -= AVIF_JPEG_MAX_MARKER_DATA_LENGTH;
         }
+        AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(remainingExif.data, remainingExif.size);
         jpeg_write_marker(&cinfo, JPEG_APP0 + 1, remainingExif.data, (unsigned int)remainingExif.size);
         avifRWDataFree(&exif);
     } else if (avifImageGetExifOrientationFromIrotImir(avif) != 1) {
@@ -1379,6 +1396,7 @@ avifBool avifJPEGWrite(const char * outputFilename, const avifImage * avif, int
             }
             memcpy(xmp.data, AVIF_JPEG_STANDARD_XMP_TAG, AVIF_JPEG_STANDARD_XMP_TAG_LENGTH);
             memcpy(xmp.data + AVIF_JPEG_STANDARD_XMP_TAG_LENGTH, avif->xmp.data, avif->xmp.size);
+            AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(xmp.data, xmp.size);
             jpeg_write_marker(&cinfo, JPEG_APP0 + 1, xmp.data, (unsigned int)xmp.size);
             avifRWDataFree(&xmp);
         }
@@ -1386,7 +1404,9 @@ avifBool avifJPEGWrite(const char * outputFilename, const avifImage * avif, int
 
     while (cinfo.next_scanline < cinfo.image_height) {
         row_pointer[0] = &rgb.pixels[cinfo.next_scanline * rgb.rowBytes];
-        (void)jpeg_write_scanlines(&cinfo, row_pointer, 1);
+        if (jpeg_write_scanlines(&cinfo, row_pointer, 1) < 1) {
+            goto cleanup;
+        }
     }
 
     jpeg_finish_compress(&cinfo);
diff --git a/include/avif/internal.h b/include/avif/internal.h
index ccee529955..a8971ac17c 100644
--- a/include/avif/internal.h
+++ b/include/avif/internal.h
@@ -6,6 +6,19 @@
 
 #include "avif/avif.h" // IWYU pragma: export
 
+#if defined(__clang__) && defined(__has_feature)
+#if __has_feature(memory_sanitizer)
+#include <sanitizer/msan_interface.h>
+#define AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) __msan_unpoison(address, size)
+#endif
+#endif
+
+#if !defined(AVIF_ANNOTATE_MEMORY_IS_INITIALIZED)
+#define AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
+    do {                                                   \
+    } while (0)
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/codec_aom.c b/src/codec_aom.c
index 396c32f40a..340b63a134 100644
--- a/src/codec_aom.c
+++ b/src/codec_aom.c
@@ -1144,6 +1144,7 @@ static avifResult aomCodecEncodeImage(avifCodec * codec,
             break;
         }
         if (pkt->kind == AOM_CODEC_CX_FRAME_PKT) {
+            AVIF_ANNOTATE_MEMORY_IS_INITIALIZED(pkt->data.frame.buf, pkt->data.frame.sz);
             AVIF_CHECKRES(
                 avifCodecEncodeOutputAddSample(output, pkt->data.frame.buf, pkt->data.frame.sz, (pkt->data.frame.flags & AOM_FRAME_IS_KEY)));
         }