major vulnerability· requires attention

FFmpeg is a widely deployed media library in servers and apps; this heap overflow can lead to RCE when transcoding untrusted subtitles, impacting many organizations' media processing pipelines.

Applications

CVE-2026-125209

8.5

High

EPSS n/aPatch available

Heap overflow in FFmpeg dvdsub encoder enabling possible RCE when transcoding crafted subtitles

exploited

No known exploitation not in CISA KEV as of our last sync

fix

Patch available see the advisory in the references

likelihood

No EPSS score yet

Published 9 Nov 2026Analysed here 10 Nov 2026CVSS scored by the publisher (CNA)

common questions

Is CVE-2026-125209 being exploited?

Not confirmed. CVE-2026-125209 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.

How severe is CVE-2026-125209?

CVE-2026-125209 is rated High with a CVSS score of 8.5. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-125209?

Yes. A fix has been recorded for CVE-2026-125209. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-125209 affect?

CVE-2026-125209 affects FFmpeg < 8.1.3, FFmpeg 9.x < 9.0.2, Any app using FFmpeg's dvdsub encoder for subtitle transcoding. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-125209?

Upgrade to FFmpeg 8.1.3 or 9.0.2; avoid processing untrusted subtitle files.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary

technical analysis

affected

FFmpeg < 8.1.3FFmpeg 9.x < 9.0.2Any app using FFmpeg's dvdsub encoder for subtitle transcoding

impact

Heap buffer overflow during dvdsub subtitle encoding; can crash processes or enable remote code execution via crafted bitmap subtitles.

action required

Patch when possible

affected versions

FFmpeg

affected< 8.1.3
affected>= 9.0 and < 9.0.2

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

timeline

9 Nov 2026Published
9 Nov 2026CVE record last updated · same day later
10 Nov 2026Analysed by vulneraibility.com · same day later

how to fix

Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.

references

NVD CVE.org CVE Details Source

5 references in the CVE record: 1 advisory, 1 patch, 3 links

Advisoryvulncheck.com /advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-heap-buffer-overflow-via-dv
Patchgithub.com /FFmpeg/FFmpeg/commit/8702f12c9daa199cc4d7c17164b13c3cdcdc2436
Linkcode.ffmpeg.org /FFmpeg/FFmpeg/pulls/24486
Linkgithub.com /FFmpeg/FFmpeg/blob/n9.0.1/libavcodec/dvdsubenc.c#L344
Linkgithub.com /FFmpeg/FFmpeg

sources

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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