diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index 93e9eb6ae7d69bb4dce3c7784d6d82c9977a0bf3..c705df3d5933c0191cbb6beb6d1a1506828248d7 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -271,6 +271,7 @@ uint8_t *av_packet_new_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
     data = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
     if (!data)
         return NULL;
+    memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
 
     ret = av_packet_add_side_data(pkt, type, data, size);
     if (ret < 0) {