CVE-2026-125223: FFmpeg memory leak in VP9 decoder

Summary

FFmpeg 8.0 through 9.0.2 contains a memory leak vulnerability in the VP9 decoder that allows attackers to exhaust memory because vp9_decode_frame() skips resetting the CBS fragment on error paths. Attackers can supply a crafted VP9 stream with invalid tile sizes decoded with slice threading to leak packet buffers and units, exhausting memory in the decoding application.

cve.now Index

6Pcve.now Index 6 of 100 · methodology v3 · provisional

Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
Exposure?/25Unknown. No advisory context yet
Reach?/20Unknown. No tracked technology or package matched
Severity5.7/10CVSS 5.7
No patch0/5No signal

What would change the score

Would score about 61 if added to CISA KEV
Would score about 56 if CISA's SSVC rates exploitation active
Would score about 28 if advisories confirm default setups are exposed

How the score works · Rankings

What to do

Apply the patch listed under Evidence.

Timeline

Nov 9, 2026, 7:11 PM UTCCVE published
Nov 9, 2026, 7:15 PM UTCFirst seen by cve.now

Affected versions

FFmpeg FFmpeg
From 8.0 · through 9.0.2

Evidence 5

Corrections

None so far.

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Questions about CVE-2026-125223

Is CVE-2026-125223 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

Which versions are affected by CVE-2026-125223?

FFmpeg: from 8.0 through 9.0.2.Source: cve.now feed data

FFmpeg 8.0 through 9.0.2 Memory Leak in VP9 Decoder via vp9_decode_frame