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FFmpeg through 9.0.2 SGI Encoder Out-of-Bounds Read via sgienc.c

6.9MediumCNA
Exploited
No known exploitation
Fix
Fix or patch referenced
Who is exposed
Not reported

Do first: Apply the patch listed under Evidence.

Published
Last modified
7/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

The FFmpeg SGI encoder (sgienc.c) has an out-of-bounds read that an attacker can trigger locally, without logging in, by supplying a video with a display matrix that causes an autorotate vertical flip, but it requires a user to act, such as transcoding that file to SGI format. Successful exploitation can crash the FFmpeg process by reading pixel data far outside the frame.

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

Read the original description

FFmpeg through 9.0.2 contains an out-of-bounds read vulnerability in the SGI encoder's encode_frame() in libavcodec/sgienc.c, where unsigned size variables mis-handle negative linesize frames. Attackers can supply a video whose display matrix triggers autorotate vflip, so transcoding to SGI images reads pixel data far outside the frame and crashes the process.

cve.now Index

7Pcve.now Index 7 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure?/25Unknown. No advisory context yet
  • Reach?/20Unknown. No tracked technology or package matched
  • Severity6.9/10CVSS 6.9
  • No patch0/5No signal

What would change the score

  • Would score about 62 if added to CISA KEV
  • Would score about 57 if CISA's SSVC rates exploitation active
  • Would score about 29 if advisories confirm default setups are exposed

What to do

  • Apply the patch listed under Evidence.

Timeline

  1. CVE published
  2. First seen by cve.now

Affected versions

  • FFmpeg FFmpeg

    through 9.0.2

Evidence 5

  1. Patch
  2. Report
  3. Repository
  4. Repository
  5. Link

Corrections

None so far.

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Questions about CVE-2026-125261

Is CVE-2026-125261 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by CVE-2026-125261?

FFmpeg: through 9.0.2.Source: cve.now feed data