CVE-2026-125191: FFmpeg deadlock in V4L2 M2M decoder

Summary

FFmpeg through 9.0.2 contains a reference count leak in libavcodec/v4l2_buffers.c that allows attackers to deadlock the V4L2 mem2mem decoder on multi-plane capture formats. Attackers can supply crafted H.264, HEVC, or VP9 streams with resolution changes, making ff_v4l2_m2m_codec_reinit() wait forever and hang the decoding application.

cve.now Index

6Pcve.now Index 6 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
Severity5.7/10CVSS 5.7
No patch0/5No signal

What would change the score

Would score about 61 if added to CISA KEV
Would score about 56 if CISA's SSVC rates exploitation active
Would score about 28 if advisories confirm default setups are exposed

How the score works · Rankings

What to do

Apply the patch listed under Evidence.

Timeline

Nov 9, 2026, 7:11 PM UTCCVE published
Nov 9, 2026, 7:15 PM UTCFirst seen by cve.now

Affected versions

FFmpeg FFmpeg
through 9.0.2

Evidence 5

Corrections

None so far.

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Questions about CVE-2026-125191

Is CVE-2026-125191 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-2026-125191?

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

FFmpeg through 9.0.2 V4L2 M2M Decoder Deadlock via Reference Count Leak