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.
History

Mon, 09 Nov 2026 19:15:00 +0000

Type Values Removed Values Added
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.
Title FFmpeg through 9.0.2 WebP Decoder Information Disclosure via Short ALPH Chunk
First Time appeared Ffmpeg
Ffmpeg ffmpeg
Weaknesses CWE-908
CPEs cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:*
Vendors & Products Ffmpeg
Ffmpeg ffmpeg
References
Metrics cvssV3_1

{'score': 3.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 4.8, 'vector': '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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-11-09T19:10:54.228Z

Updated: 2026-11-10T19:10:55.838Z

Reserved: 2026-11-09T17:44:24.208Z

Link: CVE-2026-125098

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-11-09T19:16:50.720

Modified: 2026-11-10T21:46:35.930

Link: CVE-2026-125098

cve-icon Redhat

No data.