CVE-2026-125098

LOW 3.3

FFmpeg through 9.0.2 WebP Decoder Information Disclosure via Short ALPH Chunk

CVSS Score

3.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-908
Vendor	ffmpeg
Product	ffmpeg
Published	Nov 9, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Affected Versions

FFmpeg / FFmpeg

0 ≤ 9.0.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

code.ffmpeg.org: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25715 github.com: https://github.com/FFmpeg/FFmpeg/commit/92b318e0b33623720d9f128ad7bc5fa8277c34f7 github.com: https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/webp.c#L1257 github.com: https://github.com/FFmpeg/FFmpeg vulncheck.com: https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-webp-decoder-information-disclosure-via-short-alph-chunk

Credits

Joshua Rogers (AISLE Research) Michael Niedermayer