What is CVE-2026-125223?

CVE-2026-125223 is a medium-severity vulnerability in Ffmpeg, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 4.7/10. Published 2026-11-09.

How severe is CVE-2026-125223?

Medium severity. CVSS v3 base score is 4.7 out of 10.

Vulnerability in Ffmpeg

CVE-2026-125223

FFmpeg 8.0 through 9.0.2 contains a memory leak vulnerability in the VP9 decoder that allows attackers to exhaust memory because vp9_decode_frame() skips resetting the CBS fragment on error paths. Attackers can supply a crafted VP9 stream with invalid tile sizes decoded with slice threading to leak packet buffers and units, exhausting memory in the decoding application.

Published 2026-11-09 · last modified 2026-11-10.

CVSS v3 metric

CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Ffmpeg

Weakness classification (CWE)

CWE-401 — Missing Release of Memory after Effective Lifetime

References

code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25232 (issue-tracking)
github.com/FFmpeg/FFmpeg (product)
github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/vp9.c (technical-description)
github.com/FFmpeg/FFmpeg/commit/bcce3232016695f5e482867519c45727a0a2a2c9 (patch)
www.vulncheck.com/advisories/ffmpeg-8.0-through-9.0.2-memory-leak-in-vp9-decode… (third-party-advisory)

Frequently asked questions

What is CVE-2026-125223?: CVE-2026-125223 is a medium-severity vulnerability in Ffmpeg, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 4.7/10. Published 2026-11-09.
How severe is CVE-2026-125223?: Medium severity. CVSS v3 base score is 4.7 out of 10.