Commit c4a4d5f72a for ffmpeg

commit c4a4d5f72a7d89de23043415a0a45090c51c502a
Author: Michael Niedermayer <michael@niedermayer.cc>
Date:   Fri Oct 16 22:21:59 2026 +0200

    avcodec/xsubenc: reject subtitles without rectangles

    Fixes: null pointer dereference
    Fixes: L22GwbO9rtWF
    Fixes: AISLE-2026-0150-00413
    Null pointer dereference Replicated through API with ASAN

    Found-by: Joshua Rogers <joshua.rogers@aisle.com>
    Rejecting the subtitle with AVERROR(EINVAL) was suggested in the report.

diff --git a/libavcodec/xsubenc.c b/libavcodec/xsubenc.c
index 6f417c5958..9e43213ac2 100644
--- a/libavcodec/xsubenc.c
+++ b/libavcodec/xsubenc.c
@@ -128,8 +128,13 @@ static int xsub_encode(AVCodecContext *avctx, unsigned char *buf,
         return AVERROR_BUFFER_TOO_SMALL;
     }

+    if (!h->num_rects) {
+        av_log(avctx, AV_LOG_ERROR, "No subtitle rectangle to encode.\n");
+        return AVERROR(EINVAL);
+    }
+
     // TODO: support multiple rects
-    if (h->num_rects != 1)
+    if (h->num_rects > 1)
         av_log(avctx, AV_LOG_WARNING, "Only single rects supported (%d in subtitle.)\n", h->num_rects);

     // TODO: render text-based subtitles into bitmaps