Commit de46025a0c for ffmpeg

commit de46025a0cdf74b2e316efe05ef2d153990fdcf5
Author: Michael Niedermayer <michael@niedermayer.cc>
Date:   Mon Oct 19 02:15:40 2026 +0200

    avformat/rtpenc: Reject packet sizes too small for the VC-2 payload header

    Fixes: heap-buffer-overflow
    Fixes: zZoxZuoiTRhn

    Out of array write Replicated through UnModified FFmpeg with ASAN

    Found during triage of the security report TwYfznAFyatl (#22717)

diff --git a/libavformat/rtpenc.c b/libavformat/rtpenc.c
index b3a5b0ff35..8f14fee073 100644
--- a/libavformat/rtpenc.c
+++ b/libavformat/rtpenc.c
@@ -204,6 +204,7 @@ static int rtp_write_header(AVFormatContext *s1)
             ret = AVERROR_EXPERIMENTAL;
             goto fail;
         }
+        payload_header_size = 20;
         break;
     case AV_CODEC_ID_H263:
         if (s->flags & FF_RTP_FLAG_RFC2190) {