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FFmpeg through 9.0.2 WebP Decoder Information Disclosure via Short ALPH Chunk

4.8MediumCNA
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
5/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

FFmpeg, a widely used multimedia library, contains a flaw in its WebP image decoder that can leak small amounts of previously decoded pixel data. An attacker with local access, with no login needed, can get a victim to open a specially crafted WebP image, but the victim must take an action to trigger it.

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 information disclosure vulnerability in vp8_lossy_decode_alpha() in libavcodec/webp.c that leaves alpha plane memory uninitialized for short uncompressed ALPH chunks. Attackers can supply a crafted WebP image whose ALPH chunk is shorter than width * height to disclose stale pixel data from previously decoded frames.

cve.now Index

5Pcve.now Index 5 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
  • Severity4.8/10CVSS 4.8
  • No patch0/5No signal

What would change the score

  • Would score about 60 if added to CISA KEV
  • Would score about 55 if CISA's SSVC rates exploitation active
  • Would score about 27 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.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-125098

Is CVE-2026-125098 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-2026-125098?

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