diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index fb1c9ca9ec..f0405b6d02 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1096,6 +1096,16 @@ enum AVPacketSideDataType {
      * side data includes updated metadata which appeared in the stream.
      */
     AV_PKT_DATA_METADATA_UPDATE,
+
+    /**
+     * The number of side data elements (in fact a bit more than it).
+     * This is not part of the public API/ABI in the sense that it may
+     * change when new side data types are added.
+     * This must stay the last enum value.
+     * If its value becomes huge, some code using it
+     * needs to be updated as it assumes it to be smaller than other limits.
+     */
+    AV_PKT_DATA_NB
 };
 
 typedef struct AVPacketSideData {
diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index 6aae811361..1814c99c71 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -306,11 +306,12 @@ uint8_t *av_packet_new_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
 {
     int elems = pkt->side_data_elems;
 
-    if ((unsigned)elems + 1 > INT_MAX / sizeof(*pkt->side_data))
+    if ((unsigned)elems + 1 > AV_PKT_DATA_NB)
         return NULL;
     if ((unsigned)size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
         return NULL;
 
+
     pkt->side_data = av_realloc(pkt->side_data,
                                 (elems + 1) * sizeof(*pkt->side_data));
     if (!pkt->side_data)
@@ -401,6 +402,9 @@ int av_packet_split_side_data(AVPacket *pkt){
             p-= size+5;
         }
 
+        if (i > AV_PKT_DATA_NB)
+            return AVERROR(ERANGE);
+
         pkt->side_data = av_malloc_array(i, sizeof(*pkt->side_data));
         if (!pkt->side_data)
             return AVERROR(ENOMEM);