CVE-2026-125243: 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, 19:33 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
Since the vulnerability affects FFmpeg versions up to 9.0.2, users should upgrade to a version later than 9.0.2 once a fix is released. Until then, avoid processing untrusted JPEG-LS images with the affected FFmpeg versions.
Description
CVE-2026-125243 is a medium severity vulnerability in FFmpeg up to version 9.0.2. It involves an uninitialized memory disclosure in the JPEG-LS decoder component, specifically in ff_jpegls_decode_picture(). A crafted single-component JPEG-LS image with the ILV byte set to 1 can cause decoded GRAY16 frames to leak leftover heap memory.
References
- code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25303 (opens in a new tab)
- github.com/FFmpeg/FFmpeg/commit/60bc31fcf6543505e6d2fc1a9399cca95f54ba4d (opens in a new tab)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/jpeglsdec.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-jpeg-ls-decoder (opens in a new tab)