Vulnerability in Ffmpeg
CVE-2026-125187
FFmpeg through 9.0.2 contains a reachable assertion vulnerability in the TTA encoder's tta_encode_frame() in libavcodec/ttaenc.c, which never reserves output packet space for the 4-byte CRC. Attackers can supply audio whose sample values and length produce a small, poorly compressible final frame, triggering the av_assert0() in flush_put_bits() and aborting applications transcoding to TTA.
Published · last modified .
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/25694 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/ttaenc.c (technical-description)
- github.com/FFmpeg/FFmpeg/commit/29a629e788c4343ff2e923095b8f38769fe2e470 (patch)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-tta-encoder-reachable-asserti… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125187?
- CVE-2026-125187 is a medium-severity vulnerability in Ffmpeg, classified under Reachable Assertion. CVSS score: 5.5/10. Published 2026-11-09.
- How severe is CVE-2026-125187?
- Medium severity. CVSS v3 base score is 5.5 out of 10.