Prior to ffmpeg version 4.3, the tty demuxer did not have a 'read_probe' function assigned to it. By crafting a legitimate "ffconcat" file that references an image, followed by a file the triggers the tty demuxer, the contents of the second file will be copied into the output file verbatim (as long as the -vcodec copy option is passed to ffmpeg).
{
"sources": [
{
"imported": "2025-10-18T14:07:17.119Z",
"url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2021-3566",
"modified": "2024-11-21T06:21:51.763Z",
"id": "CVE-2021-3566",
"published": "2021-08-05T21:15:12.783Z",
"html_url": "https://nvd.nist.gov/vuln/detail/CVE-2021-3566"
}
],
"license": "CC-BY-4.0"
}