CVE-2026-125269: FFmpeg through 9.0.2 Double Free via cbs_sei_delete_message in cbs_sei.c

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 2.6 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

7.3 High

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 Double Free via cbs_sei_delete_message in cbs_sei.c

FFmpeg through 9.0.2 contains a double free vulnerability in libavcodec/cbs_sei.c where cbs_sei_delete_message() leaves a stale extension_data reference that ff_cbs_sei_add_message() reuses. Attackers can supply a crafted H.264 stream with a display orientation SEI message followed by payload extension data, processed by h264_metadata with display_orientation=insert, to corrupt heap memory.

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