CVE-2026-125096: FFmpeg · Use of Uninitialized Resource
Affects FFmpegSource CVE Database V5
Not known to be exploited · CVSS 4.8 Medium.
Data as of 9 Nov 2026, 20:47 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 4.8 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 3.3 |
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 9 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| FFmpegFFmpeg | Affected
| Fixed in– |
GitHubFFmpegpkg:github/FFmpegOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is available, avoid processing untrusted Tiertex SEQ files or use alternative codecs. Monitor FFmpeg vendor advisories for updates addressing this issue.
Description
CVE-2026-125096 is a medium severity vulnerability in FFmpeg through version 9.0.2. It involves an uninitialized memory disclosure in the libavcodec/tiertexseqv.c component. An attacker can craft a malicious Tiertex SEQ file that triggers a failed run-length encoding (RLE) unpacking, causing the function seq_decode_op1() to copy uninitialized 64-byte stack memory into decoded frames. This leads to leakage of stack contents in the output video frames.
References
- code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25715 (opens in a new tab)
- github.com/FFmpeg/FFmpeg/commit/c896bbb24535685509a816af09665cb73bf2d0c7 (opens in a new tab)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/tiertexseqv.c (opens in a new tab)
- github.com/FFmpeg/FFmpeg (opens in a new tab)
- vulncheck.com/advisories/ffmpeg-through-9.0.2-uninitialized-memory-disclosure-via-tiertex-seq-decoder (opens in a new tab)