FFmpeg through 9.0.2 Double Free via cbs_sei_delete_message in cbs_sei.c
Affects FFmpeg through 9.0.2 when a stream is processed by h264_metadata with display_orientation=insert and contains a display orientation SEI message with payload extension data. No fix is listed in the checked facts.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fix or patch referenced
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. FFmpeg version through 9.0.2 is affected Stream is processed by h264_metadata with display_orientation=insert and contains a display orientation SEI message followed by payload extension data
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 12/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
FFmpeg, through a version fixed in its 9.0.x series, has a double-free bug in its SEI metadata handling that can corrupt heap memory. An attacker can exploit it locally, without logging in, by getting a user to process a crafted H.264 stream with the h264_metadata filter set to insert display orientation.
Read the original description
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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure5/25Specific setups only
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.3/10CVSS 7.3
- No patch0/5No signal
What would change the score
- Would score about 62 if added to CISA KEV
- Would score about 57 if CISA's SSVC rates exploitation active
- Would score about 22 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
FFmpeg version through 9.0.2 is affected Stream is processed by h264_metadata with display_orientation=insert and contains a display orientation SEI message followed by payload extension dataApply the patch listed under Evidence.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- FFmpeg FFmpeg
through 9.0.2
Evidence 5
- Patch
- Report
- Repository
- Repository
- Link
Corrections
None so far.
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Questions about CVE-2026-125269
Is CVE-2026-125269 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
What does this mean?
A flaw in cbs_sei_delete_message in cbs_sei.c causes a double free, which can corrupt heap memory when a crafted H.264 stream is processed.Source: vulncheck.com
Which versions are affected by CVE-2026-125269?
FFmpeg: through 9.0.2.Source: cve.now feed data
Am I affected, and how do I check?
FFmpeg versions through 9.0.2 are listed as affected. The bug needs the h264_metadata filter with display_orientation=insert and a stream with a display orientation SEI message followed by payload extension data. Check the version with ffmpeg -version and check whether the command line or filter settings use h264_metadata with display_orientation=insert.Source: vulncheck.com
How do I fix CVE-2026-125269?
The checked facts do not name a fixed version. Check the FFmpeg project or your distribution's advisories for a release newer than 9.0.2 that includes the fix.Source: vulncheck.com