Vulnerability in Ffmpeg
CVE-2026-125220
FFmpeg through 9.0.2 contains a deadlock vulnerability in mimic_decode_frame() in libavcodec/mimic.c that fails to report frame progress when init_get_bits8() fails. Attackers can supply a crafted file with an oversized Mimic intra frame followed by inter frames to hang frame-threaded decoding indefinitely.
Published .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25718 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/mimic.c (technical-description)
- Patch Commit (patch)
- VulnCheck Advisory: FFmpeg through 9.0.2 Mimic Decoder Deadlock via Frame Threading Failure (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125220?
- CVE-2026-125220 is a medium-severity vulnerability in Ffmpeg, classified under CWE-833. CVSS score: 5.5/10. Published 2026-11-09.
- How severe is CVE-2026-125220?
- Medium severity. CVSS v3 base score is 5.5 out of 10.