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VulnerabilityPublished

CVE-2026-125243: FFmpeg · Use of Uninitialized Resource

Affects FFmpegSource CVE Database V5

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Not known to be exploited · CVSS 4.8 Medium.

Data as of 9 Nov 2026, 19:33 UTC

CVSS 4.0 base score
4.8Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.04.8
CNA (VulnCheck)CVSS 3.13.3
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
FFmpegFFmpegAffected
  • <=9.0.2
Fixed in–
GitHubFFmpegpkg:github/FFmpegOther threatsAffected
  • <=9.0.2
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

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