diff --git a/libavformat/rtpdec_mpeg4.c b/libavformat/rtpdec_mpeg4.c
index 34c7950bcc..0b54d417cf 100644
--- a/libavformat/rtpdec_mpeg4.c
+++ b/libavformat/rtpdec_mpeg4.c
@@ -132,7 +132,7 @@ static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf, int len)
        length in bits */
     au_headers_length = AV_RB16(buf);
 
-    if (au_headers_length > RTP_MAX_PACKET_LENGTH)
+    if (au_headers_length == 0 || au_headers_length > RTP_MAX_PACKET_LENGTH)
       return -1;
 
     data->au_headers_length_bytes = (au_headers_length + 7) / 8;