Commit bda6ec0d52 for ffmpeg

commit bda6ec0d52d8334af72cb3e4ea43c6fbe91e015d
Author: Michael Niedermayer <michael@niedermayer.cc>
Date:   Thu Oct 8 01:40:31 2026 +0200

    avformat/iff: Check the CMAP read size

    Fixes: use of uninitialized memory
    Fixes: 5bX0wHRp9uuN
    Use of uninitialized memory Replicated through UnModified FFmpeg (ffprobe) with Valgrind
    Found during triage of the security report fo0u77U9tJ8g

diff --git a/libavformat/iff.c b/libavformat/iff.c
index a8c10f6286..be400e48d5 100644
--- a/libavformat/iff.c
+++ b/libavformat/iff.c
@@ -568,7 +568,7 @@ static int iff_read_header(AVFormatContext *s)
                                      data_size + IFF_EXTRA_VIDEO_SIZE);
             if (res < 0)
                 return res;
-            if ((res = avio_read(pb, stv->codecpar->extradata + IFF_EXTRA_VIDEO_SIZE, data_size)) < 0) {
+            if ((res = ffio_read_size(pb, stv->codecpar->extradata + IFF_EXTRA_VIDEO_SIZE, data_size)) < 0) {
                 av_freep(&stv->codecpar->extradata);
                 stv->codecpar->extradata_size = 0;
                 return res;