Commit 0af7c262a1 for ffmpeg

commit 0af7c262a12b8d68694ff778a5877aa5b8aea0f5
Author: Michael Niedermayer <michael@niedermayer.cc>
Date:   Sun Nov 15 19:34:05 2026 +0100

    avformat/avisynth: do not select the demuxer by file extension

    Fixes: Arbitrary code execution
    Fixes: acf_a81d9fbe1d00a6ac6de3984d55253e07
    Fixes: CdQERK5i6h83

    Code execution Replicated through UnModified FFmpeg with AviSynth+ 3.7.6

diff --git a/doc/faq.texi b/doc/faq.texi
index a9872fc2d2..6a3c1db612 100644
--- a/doc/faq.texi
+++ b/doc/faq.texi
@@ -282,7 +282,7 @@ DirectShowSource("C:\path to your file\yourfile.asf")
 @end example
 ... and then feed that text file to ffmpeg:
 @example
-ffmpeg -i input.avs
+ffmpeg -f avisynth -i input.avs
 @end example

 For ANY other help on AviSynth, please visit the
diff --git a/libavformat/avisynth.c b/libavformat/avisynth.c
index cb2be10925..7133860466 100644
--- a/libavformat/avisynth.c
+++ b/libavformat/avisynth.c
@@ -1150,7 +1150,6 @@ static const AVClass avisynth_demuxer_class = {
 const FFInputFormat ff_avisynth_demuxer = {
     .p.name         = "avisynth",
     .p.long_name    = NULL_IF_CONFIG_SMALL("AviSynth script"),
-    .p.extensions   = "avs",
     .p.priv_class   = &avisynth_demuxer_class,
     .priv_data_size = sizeof(AviSynthContext),
     .read_header    = avisynth_read_header,