diff --git a/src/dec/alpha_dec.c b/src/dec/alpha_dec.c
index b3cb4edf..2632073f 100644
--- a/src/dec/alpha_dec.c
+++ b/src/dec/alpha_dec.c
@@ -26,6 +26,8 @@
 #include "src/webp/format_constants.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 //------------------------------------------------------------------------------
 // ALPHDecoder object.
 
diff --git a/src/dec/alphai_dec.h b/src/dec/alphai_dec.h
index 6dfe5a96..44739392 100644
--- a/src/dec/alphai_dec.h
+++ b/src/dec/alphai_dec.h
@@ -20,6 +20,8 @@
 #include "src/utils/filters_utils.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/dec/buffer_dec.c b/src/dec/buffer_dec.c
index 5a4a3862..787e6406 100644
--- a/src/dec/buffer_dec.c
+++ b/src/dec/buffer_dec.c
@@ -22,6 +22,8 @@
 #include "src/webp/decode.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 //------------------------------------------------------------------------------
 // WebPDecBuffer
 
diff --git a/src/dec/frame_dec.c b/src/dec/frame_dec.c
index dcb691e9..806e294d 100644
--- a/src/dec/frame_dec.c
+++ b/src/dec/frame_dec.c
@@ -26,6 +26,8 @@
 #include "src/webp/decode.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 //------------------------------------------------------------------------------
 // Main reconstruction function.
 
@@ -47,7 +49,7 @@ static int CheckMode(int mb_x, int mb_y, int mode) {
 }
 
 static void Copy32b(uint8_t* const dst, const uint8_t* const src) {
-  memcpy(dst, src, 4);
+  WEBP_UNSAFE_MEMCPY(dst, src, 4);
 }
 
 static WEBP_INLINE void DoTransform(uint32_t bits, const int16_t* const src,
@@ -131,9 +133,9 @@ static void ReconstructRow(const VP8Decoder* const dec,
       int n;
 
       if (mb_y > 0) {
-        memcpy(y_dst - BPS, top_yuv[0].y, 16);
-        memcpy(u_dst - BPS, top_yuv[0].u, 8);
-        memcpy(v_dst - BPS, top_yuv[0].v, 8);
+        WEBP_UNSAFE_MEMCPY(y_dst - BPS, top_yuv[0].y, 16);
+        WEBP_UNSAFE_MEMCPY(u_dst - BPS, top_yuv[0].u, 8);
+        WEBP_UNSAFE_MEMCPY(v_dst - BPS, top_yuv[0].v, 8);
       }
 
       // predict and add residuals
@@ -144,7 +146,7 @@ static void ReconstructRow(const VP8Decoder* const dec,
           if (mb_x >= dec->mb_w - 1) {  // on rightmost border
             memset(top_right, top_yuv[0].y[15], sizeof(*top_right));
           } else {
-            memcpy(top_right, top_yuv[1].y, sizeof(*top_right));
+            WEBP_UNSAFE_MEMCPY(top_right, top_yuv[1].y, sizeof(*top_right));
           }
         }
         // replicate the top-right pixels below
@@ -177,9 +179,9 @@ static void ReconstructRow(const VP8Decoder* const dec,
 
       // stash away top samples for next block
       if (mb_y < dec->mb_h - 1) {
-        memcpy(top_yuv[0].y, y_dst + 15 * BPS, 16);
-        memcpy(top_yuv[0].u, u_dst + 7 * BPS, 8);
-        memcpy(top_yuv[0].v, v_dst + 7 * BPS, 8);
+        WEBP_UNSAFE_MEMCPY(top_yuv[0].y, y_dst + 15 * BPS, 16);
+        WEBP_UNSAFE_MEMCPY(top_yuv[0].u, u_dst + 7 * BPS, 8);
+        WEBP_UNSAFE_MEMCPY(top_yuv[0].v, v_dst + 7 * BPS, 8);
       }
     }
     // Transfer reconstructed samples from yuv_b cache to final destination.
@@ -190,11 +192,14 @@ static void ReconstructRow(const VP8Decoder* const dec,
       uint8_t* const u_out = dec->cache_u + mb_x * 8 + uv_offset;
       uint8_t* const v_out = dec->cache_v + mb_x * 8 + uv_offset;
       for (j = 0; j < 16; ++j) {
-        memcpy(y_out + j * dec->cache_y_stride, y_dst + j * BPS, 16);
+        WEBP_UNSAFE_MEMCPY(y_out + j * dec->cache_y_stride, y_dst + j * BPS,
+                           16);
       }
       for (j = 0; j < 8; ++j) {
-        memcpy(u_out + j * dec->cache_uv_stride, u_dst + j * BPS, 8);
-        memcpy(v_out + j * dec->cache_uv_stride, v_dst + j * BPS, 8);
+        WEBP_UNSAFE_MEMCPY(u_out + j * dec->cache_uv_stride, u_dst + j * BPS,
+                           8);
+        WEBP_UNSAFE_MEMCPY(v_out + j * dec->cache_uv_stride, v_dst + j * BPS,
+                           8);
       }
     }
   }
@@ -494,9 +499,12 @@ static int FinishRow(void* arg1, void* arg2) {
   // rotate top samples if needed
   if (cache_id + 1 == dec->num_caches) {
     if (!is_last_row) {
-      memcpy(dec->cache_y - ysize, ydst + 16 * dec->cache_y_stride, ysize);
-      memcpy(dec->cache_u - uvsize, udst + 8 * dec->cache_uv_stride, uvsize);
-      memcpy(dec->cache_v - uvsize, vdst + 8 * dec->cache_uv_stride, uvsize);
+      WEBP_UNSAFE_MEMCPY(dec->cache_y - ysize, ydst + 16 * dec->cache_y_stride,
+                         ysize);
+      WEBP_UNSAFE_MEMCPY(dec->cache_u - uvsize, udst + 8 * dec->cache_uv_stride,
+                         uvsize);
+      WEBP_UNSAFE_MEMCPY(dec->cache_v - uvsize, vdst + 8 * dec->cache_uv_stride,
+                         uvsize);
     }
   }
 
diff --git a/src/dec/idec_dec.c b/src/dec/idec_dec.c
index 3eab0acb..dd0e0879 100644
--- a/src/dec/idec_dec.c
+++ b/src/dec/idec_dec.c
@@ -27,6 +27,8 @@
 #include "src/webp/format_constants.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 // In append mode, buffer allocations increase as multiples of this value.
 // Needs to be a power of 2.
 #define CHUNK_SIZE 4096
@@ -196,7 +198,7 @@ WEBP_NODISCARD static int AppendToMemBuffer(WebPIDecoder* const idec,
     uint8_t* const new_buf =
         (uint8_t*)WebPSafeMalloc(extra_size, sizeof(*new_buf));
     if (new_buf == NULL) return 0;
-    if (old_base != NULL) memcpy(new_buf, old_base, current_size);
+    if (old_base != NULL) WEBP_UNSAFE_MEMCPY(new_buf, old_base, current_size);
     WebPSafeFree(mem->buf);
     mem->buf = new_buf;
     mem->buf_size = (size_t)extra_size;
@@ -205,7 +207,7 @@ WEBP_NODISCARD static int AppendToMemBuffer(WebPIDecoder* const idec,
   }
 
   assert(mem->buf != NULL);
-  memcpy(mem->buf + mem->end, data, data_size);
+  WEBP_UNSAFE_MEMCPY(mem->buf + mem->end, data, data_size);
   mem->end += data_size;
   assert(mem->end <= mem->buf_size);
 
@@ -401,7 +403,7 @@ static VP8StatusCode CopyParts0Data(WebPIDecoder* const idec) {
     if (part0_buf == NULL) {
       return VP8_STATUS_OUT_OF_MEMORY;
     }
-    memcpy(part0_buf, br->buf, part_size);
+    WEBP_UNSAFE_MEMCPY(part0_buf, br->buf, part_size);
     mem->part0_buf = part0_buf;
     VP8BitReaderSetBuffer(br, part0_buf, part_size);
   } else {
diff --git a/src/dec/io_dec.c b/src/dec/io_dec.c
index 8230f6bf..cea04225 100644
--- a/src/dec/io_dec.c
+++ b/src/dec/io_dec.c
@@ -27,6 +27,8 @@
 #include "src/webp/decode.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 //------------------------------------------------------------------------------
 // Main YUV<->RGB conversion functions
 
@@ -100,9 +102,9 @@ static int EmitFancyRGB(const VP8Io* const io, WebPDecParams* const p) {
   cur_y += io->y_stride;
   if (io->crop_top + y_end < io->crop_bottom) {
     // Save the unfinished samples for next call (as we're not done yet).
-    memcpy(p->tmp_y, cur_y, mb_w * sizeof(*p->tmp_y));
-    memcpy(p->tmp_u, cur_u, uv_w * sizeof(*p->tmp_u));
-    memcpy(p->tmp_v, cur_v, uv_w * sizeof(*p->tmp_v));
+    WEBP_UNSAFE_MEMCPY(p->tmp_y, cur_y, mb_w * sizeof(*p->tmp_y));
+    WEBP_UNSAFE_MEMCPY(p->tmp_u, cur_u, uv_w * sizeof(*p->tmp_u));
+    WEBP_UNSAFE_MEMCPY(p->tmp_v, cur_v, uv_w * sizeof(*p->tmp_v));
     // The fancy upsampler leaves a row unfinished behind
     // (except for the very last row)
     num_lines_out--;
@@ -140,7 +142,7 @@ static int EmitAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
   assert(expected_num_lines_out == mb_h);
   if (alpha != NULL) {
     for (j = 0; j < mb_h; ++j) {
-      memcpy(dst, alpha, mb_w * sizeof(*dst));
+      WEBP_UNSAFE_MEMCPY(dst, alpha, mb_w * sizeof(*dst));
       alpha += io->width;
       dst += buf->a_stride;
     }
diff --git a/src/dec/quant_dec.c b/src/dec/quant_dec.c
index 31b2e5b4..9194e044 100644
--- a/src/dec/quant_dec.c
+++ b/src/dec/quant_dec.c
@@ -17,6 +17,8 @@
 #include "src/utils/bit_reader_utils.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 static WEBP_INLINE int clip(int v, int M) { return v < 0 ? 0 : v > M ? M : v; }
 
 // Paragraph 14.1
diff --git a/src/dec/tree_dec.c b/src/dec/tree_dec.c
index 58c8e040..bd93d53b 100644
--- a/src/dec/tree_dec.c
+++ b/src/dec/tree_dec.c
@@ -21,6 +21,8 @@
 #include "src/utils/bit_reader_utils.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #if !defined(USE_GENERIC_TREE)
 #if !defined(__arm__) && !defined(_M_ARM) && !WEBP_AARCH64 && !defined(__wasm__)
 // using a table is ~1-2% slower on ARM. Prefer the coded-tree approach then.
@@ -316,7 +318,7 @@ static void ParseIntraMode(VP8BitReader* const br, VP8Decoder* const dec,
 #endif  // USE_GENERIC_TREE
         top[x] = ymode;
       }
-      memcpy(modes, top, 4 * sizeof(*top));
+      WEBP_UNSAFE_MEMCPY(modes, top, 4 * sizeof(*top));
       modes += 4;
       left[y] = ymode;
     }
diff --git a/src/dec/vp8_dec.c b/src/dec/vp8_dec.c
index 3225cb98..b43fb556 100644
--- a/src/dec/vp8_dec.c
+++ b/src/dec/vp8_dec.c
@@ -32,6 +32,8 @@
 #include "src/webp/format_constants.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 //------------------------------------------------------------------------------
 
 int WebPGetDecoderVersion(void) {
diff --git a/src/dec/vp8_dec.h b/src/dec/vp8_dec.h
index 2be0d799..a0f66ba6 100644
--- a/src/dec/vp8_dec.h
+++ b/src/dec/vp8_dec.h
@@ -19,6 +19,8 @@
 #include "src/webp/decode.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/dec/vp8i_dec.h b/src/dec/vp8i_dec.h
index 62720ac7..28ec15c5 100644
--- a/src/dec/vp8i_dec.h
+++ b/src/dec/vp8i_dec.h
@@ -27,6 +27,8 @@
 #include "src/webp/decode.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/dec/vp8l_dec.c b/src/dec/vp8l_dec.c
index b584d3ff..d25b3dab 100644
--- a/src/dec/vp8l_dec.c
+++ b/src/dec/vp8l_dec.c
@@ -34,6 +34,8 @@
 #include "src/webp/format_constants.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #define NUM_ARGB_CACHE_ROWS 16
 
 static const int kCodeLengthLiterals = 16;
@@ -843,7 +845,7 @@ static void ApplyInverseTransforms(VP8LDecoder* const dec, int start_row,
   }
   if (rows_in != rows_out) {
     // No transform called, hence just copy.
-    memcpy(rows_out, rows_in, cache_pixs * sizeof(*rows_out));
+    WEBP_UNSAFE_MEMCPY(rows_out, rows_in, cache_pixs * sizeof(*rows_out));
   }
 }
 
@@ -1022,7 +1024,7 @@ static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
         break;
       case 2:
 #if !defined(WORDS_BIGENDIAN)
-        memcpy(&pattern, src, sizeof(uint16_t));
+        WEBP_UNSAFE_MEMCPY(&pattern, src, sizeof(uint16_t));
 #else
         pattern = ((uint32_t)src[0] << 8) | src[1];
 #endif
@@ -1035,7 +1037,7 @@ static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
 #endif
         break;
       case 4:
-        memcpy(&pattern, src, sizeof(uint32_t));
+        WEBP_UNSAFE_MEMCPY(&pattern, src, sizeof(uint32_t));
         break;
       default:
         goto Copy;
@@ -1044,8 +1046,8 @@ static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) {
     return;
   }
 Copy:
-  if (dist >= length) {  // no overlap -> use memcpy()
-    memcpy(dst, src, length * sizeof(*dst));
+  if (dist >= length) {  // no overlap -> use WEBP_UNSAFE_MEMCPY()
+    WEBP_UNSAFE_MEMCPY(dst, src, length * sizeof(*dst));
   } else {
     int i;
     for (i = 0; i < length; ++i) dst[i] = src[i];
@@ -1079,11 +1081,11 @@ static WEBP_INLINE void CopyBlock32b(uint32_t* const dst, int dist,
       pattern = (uint64_t)src[0];
       pattern |= pattern << 32;
     } else {
-      memcpy(&pattern, src, sizeof(pattern));
+      WEBP_UNSAFE_MEMCPY(&pattern, src, sizeof(pattern));
     }
     CopySmallPattern32b(src, dst, length, pattern);
   } else if (dist >= length) {  // no overlap
-    memcpy(dst, src, length * sizeof(*dst));
+    WEBP_UNSAFE_MEMCPY(dst, src, length * sizeof(*dst));
   } else {
     int i;
     for (i = 0; i < length; ++i) dst[i] = src[i];
diff --git a/src/dec/vp8li_dec.h b/src/dec/vp8li_dec.h
index bffad693..cbf3ce1f 100644
--- a/src/dec/vp8li_dec.h
+++ b/src/dec/vp8li_dec.h
@@ -27,6 +27,8 @@
 #include "src/webp/format_constants.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/dec/webp_dec.c b/src/dec/webp_dec.c
index dd1a6f6c..9377d2b9 100644
--- a/src/dec/webp_dec.c
+++ b/src/dec/webp_dec.c
@@ -27,6 +27,8 @@
 #include "src/webp/mux_types.h"  // ALPHA_FLAG
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 //------------------------------------------------------------------------------
 // RIFF layout is:
 //   Offset  tag
diff --git a/src/dec/webpi_dec.h b/src/dec/webpi_dec.h
index 5aa9bc4d..506ffcc0 100644
--- a/src/dec/webpi_dec.h
+++ b/src/dec/webpi_dec.h
@@ -25,6 +25,8 @@ extern "C" {
 #include "src/webp/decode.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 //------------------------------------------------------------------------------
 // WebPDecParams: Decoding output parameters. Transient internal object.
 
diff --git a/src/demux/anim_decode.c b/src/demux/anim_decode.c
index 01ef9ce8..259aaff7 100644
--- a/src/demux/anim_decode.c
+++ b/src/demux/anim_decode.c
@@ -24,6 +24,8 @@
 #include "src/webp/mux_types.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #define NUM_CHANNELS 4
 
 // Channel extraction from a uint32_t representation of a uint8_t RGBA/BGRA
@@ -168,7 +170,7 @@ WEBP_NODISCARD static int ZeroFillCanvas(uint8_t* buf, uint32_t canvas_width,
   const uint64_t size =
       (uint64_t)canvas_width * canvas_height * NUM_CHANNELS * sizeof(*buf);
   if (!CheckSizeOverflow(size)) return 0;
-  memset(buf, 0, (size_t)size);
+  WEBP_UNSAFE_MEMSET(buf, 0, (size_t)size);
   return 1;
 }
 
@@ -179,7 +181,7 @@ static void ZeroFillFrameRect(uint8_t* buf, int buf_stride, int x_offset,
   assert(width * NUM_CHANNELS <= buf_stride);
   buf += y_offset * buf_stride + x_offset * NUM_CHANNELS;
   for (j = 0; j < height; ++j) {
-    memset(buf, 0, width * NUM_CHANNELS);
+    WEBP_UNSAFE_MEMSET(buf, 0, width * NUM_CHANNELS);
     buf += buf_stride;
   }
 }
@@ -190,7 +192,7 @@ WEBP_NODISCARD static int CopyCanvas(const uint8_t* src, uint8_t* dst,
   const uint64_t size = (uint64_t)width * height * NUM_CHANNELS;
   if (!CheckSizeOverflow(size)) return 0;
   assert(src != NULL && dst != NULL);
-  memcpy(dst, src, (size_t)size);
+  WEBP_UNSAFE_MEMCPY(dst, src, (size_t)size);
   return 1;
 }
 
@@ -456,7 +458,7 @@ void WebPAnimDecoderReset(WebPAnimDecoder* dec) {
   if (dec != NULL) {
     dec->prev_frame_timestamp = 0;
     WebPDemuxReleaseIterator(&dec->prev_iter);
-    memset(&dec->prev_iter, 0, sizeof(dec->prev_iter));
+    WEBP_UNSAFE_MEMSET(&dec->prev_iter, 0, sizeof(dec->prev_iter));
     dec->prev_frame_was_keyframe = 0;
     dec->next_frame = 1;
   }
diff --git a/src/demux/demux.c b/src/demux/demux.c
index c7c91d6b..c4f8d1a2 100644
--- a/src/demux/demux.c
+++ b/src/demux/demux.c
@@ -26,6 +26,8 @@
 #include "src/webp/mux_types.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #define DMUX_MAJ_VERSION 1
 #define DMUX_MIN_VERSION 6
 #define DMUX_REV_VERSION 0
@@ -116,7 +118,7 @@ static int RemapMemBuffer(MemBuffer* const mem, const uint8_t* data,
 
 static int InitMemBuffer(MemBuffer* const mem, const uint8_t* data,
                          size_t size) {
-  memset(mem, 0, sizeof(*mem));
+  WEBP_UNSAFE_MEMSET(mem, 0, sizeof(*mem));
   return RemapMemBuffer(mem, data, size);
 }
 
@@ -874,7 +876,7 @@ static int SetFrame(int frame_num, WebPIterator* const iter) {
 int WebPDemuxGetFrame(const WebPDemuxer* dmux, int frame, WebPIterator* iter) {
   if (iter == NULL) return 0;
 
-  memset(iter, 0, sizeof(*iter));
+  WEBP_UNSAFE_MEMSET(iter, 0, sizeof(*iter));
   iter->private_ = (void*)dmux;
   return SetFrame(frame, iter);
 }
@@ -945,7 +947,7 @@ int WebPDemuxGetChunk(const WebPDemuxer* dmux, const char fourcc[4],
                       int chunk_num, WebPChunkIterator* iter) {
   if (iter == NULL) return 0;
 
-  memset(iter, 0, sizeof(*iter));
+  WEBP_UNSAFE_MEMSET(iter, 0, sizeof(*iter));
   iter->private_ = (void*)dmux;
   return SetChunk(fourcc, chunk_num, iter);
 }
diff --git a/src/dsp/lossless.h b/src/dsp/lossless.h
index a80efcb8..7df94119 100644
--- a/src/dsp/lossless.h
+++ b/src/dsp/lossless.h
@@ -19,6 +19,8 @@
 #include "src/webp/decode.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/dsp/yuv.h b/src/dsp/yuv.h
index 52f9b14d..107c167e 100644
--- a/src/dsp/yuv.h
+++ b/src/dsp/yuv.h
@@ -40,6 +40,8 @@
 #include "src/dsp/dsp.h"
 #include "src/webp/types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 // Macros to give the offset of each channel in a uint32_t containing ARGB.
 #ifdef WORDS_BIGENDIAN
 // uint32_t 0xff000000 is 0xff,00,00,00 in memory
diff --git a/src/webp/decode.h b/src/webp/decode.h
index 0cd36655..8a57fb26 100644
--- a/src/webp/decode.h
+++ b/src/webp/decode.h
@@ -18,6 +18,8 @@
 
 #include "./types.h"
 
+WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
+
 #ifdef __cplusplus
 extern "C" {
 #endif