CVE-2026-125253: FFmpeg through 9.0.2 VP9 CBS Superframe Integer Overflow Out-of-Bounds Read

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 10 Nov 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.1%

EPSS score, percentile 2 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

5.8 Medium

CVSS v4.0 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

• 9.0.2 and earlier

Versions by product

Source: CISA KEV 2026.11.10, as of 10 Nov 2026; FIRST EPSS, as of 12 Nov 2026; CVE List, as of 12 Nov 2026. About the data.

Description

FFmpeg through 9.0.2 VP9 CBS Superframe Integer Overflow Out-of-Bounds Read

FFmpeg through 9.0.2 contains an integer overflow in cbs_vp9_split_fragment() in libavcodec/cbs_vp9.c that wraps the superframe size check on 32-bit builds. Attackers can supply a crafted VP9 packet with a forged superframe index containing near-2^32 frame sizes, causing out-of-bounds reads that crash 32-bit applications.

Source: CVE List, as of 12 Nov 2026. About the data.

What to do

Advisories and patches

• Patch Commit (Patch)

This summary is based on the CVE record as of 12 Nov 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Source: CVE List, as of 12 Nov 2026. About the data.

Timeline