CVE-2026-125191 (CVSS 4.7)

Description

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.

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CVSS v3.1 Score

4.7

MEDIUM

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

EPSS — Exploit Prediction

0.0016

Probability of exploitation

0.05%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-911 CWE-911

References

Other References

https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25682 https://github.com/FFmpeg/FFmpeg https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/v4l2_buffers.c#L274 https://github.com/FFmpeg/FFmpeg/commit/4d2d58efa9b9f3802893b1db0ea1edfbe1cc66ef https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-v4l2-m2m-decoder-deadlock-via-reference-count-leak

Frequently Asked Questions

What is CVE-2026-125191? +

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. It has a CVSS v3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2026-125191? +

CVE-2026-125191 has a CVSS v3.1 score of 4.7 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0016, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-125191? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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