diff --git a/libavcodec/aac_parser.c b/libavcodec/aac_parser.c
index a8ef2f35dd..a6c9ad1352 100644
--- a/libavcodec/aac_parser.c
+++ b/libavcodec/aac_parser.c
@@ -34,7 +34,7 @@ static int aac_sync(uint64_t state, AACAC3ParseContext *hdr_info,
     int size;
     union {
         uint64_t u64;
-        uint8_t  u8[8];
+        uint8_t  u8[8 + FF_INPUT_BUFFER_PADDING_SIZE];
     } tmp;
 
     tmp.u64 = av_be2ne64(state);
diff --git a/libavcodec/ac3_parser.c b/libavcodec/ac3_parser.c
index 83cc4e0e36..773f4c289f 100644
--- a/libavcodec/ac3_parser.c
+++ b/libavcodec/ac3_parser.c
@@ -147,7 +147,7 @@ static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
     int err;
     union {
         uint64_t u64;
-        uint8_t  u8[8];
+        uint8_t  u8[8 + FF_INPUT_BUFFER_PADDING_SIZE];
     } tmp = { av_be2ne64(state) };
     AC3HeaderInfo hdr;
     GetBitContext gbc;