Commit e00aa4bad3 for ffmpeg

commit e00aa4bad39f76e9428d03ee5537f5b2b8c2c6e2
Author: Michael Niedermayer <michael@niedermayer.cc>
Date:   Thu Oct 8 01:53:17 2026 +0200

    avformat/mpegtsenc: Do not copy extradata that does not exist

    For streams without extradata memcpy() was called with a NULL source.

    Fixes: 5M151mE1kuw5
    memcpy() from NULL Replicated through UnModified FFmpeg with UBSAN
    Found while testing the fix for the security report AISLE-2026-0111-00391

diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c
index 89d64c1f1c..7d04ad03e5 100644
--- a/libavformat/mpegtsenc.c
+++ b/libavformat/mpegtsenc.c
@@ -1906,7 +1906,8 @@ static uint8_t *h26x_prefix_aud(const uint8_t *aud, const int aud_size,
         return NULL;
     AV_WB32(data, 0x00000001);
     memcpy(data + sz, aud, aud_size);
-    memcpy(data + sz + aud_size, extra_data, extra_size);
+    if (extra_size)
+        memcpy(data + sz + aud_size, extra_data, extra_size);
     memcpy(data + sz + aud_size + extra_size, pkt->data, pkt->size);
     *size = pkt->size + sz + aud_size + extra_size;
     return data;