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VulnerabilityPublished

CVE-2026-120243: FFmpeg · Use of Uninitialized Variable

Affects FFmpegSource CVE Database V5

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Not known to be exploited · CVSS 6.8 Medium.

Data as of 1 Nov 2026, 01:21 UTC

CVSS 4.0 base score
6.8Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.06.8
CNA (VulnCheck)CVSS 3.15.5
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 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 31 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
FFmpegFFmpegAffected
  • >=2.0 <=9.0.2
Fixed in–
GitHubFFmpegpkg:github/FFmpegOther threatsAffected
  • >=2.0 <=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

Users should monitor the FFmpeg project advisories for updates addressing this issue. Until a fix is available, avoid processing untrusted Go2Meeting (G2M3/G2M4) streams to mitigate the risk of memory disclosure. Since this is a local attack vector requiring user interaction, restricting access to trusted content and users can reduce exposure.

Description

CVE-2026-120243 is a vulnerability in FFmpeg versions 2.0 through 9.0.2 involving the use of an uninitialized variable in the Go2Meeting decoder. This flaw allows attackers to leak stack memory by exploiting out-of-range palette indices in crafted G2M3/G2M4 streams. The vulnerability arises because the function kempf_restore_buf() copies uninitialized stack bytes, potentially exposing sensitive data such as pointers or stack guards.

References

Community reviews

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