CVE-2026-125176: FFmpeg memory leak in Flash SV2 decoder

Summary

FFmpeg through 9.0.2 contains an uninitialized memory read vulnerability in decode_hybrid() in libavcodec/flashsv.c that reads past decompressed data when decoding 15-bit color pixels. Attackers can supply a crafted Flash Screen Video 2 block whose inflated data ends mid-pixel to leak heap memory into decoded output frames.

cve.now Index

5Pcve.now Index 5 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
Severity4.8/10CVSS 4.8
No patch0/5No signal

What would change the score

Would score about 60 if added to CISA KEV
Would score about 55 if CISA's SSVC rates exploitation active
Would score about 27 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
through 9.0.2

Evidence 5

Corrections

None so far.

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Questions about CVE-2026-125176

Is CVE-2026-125176 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-2026-125176?

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

FFmpeg through 9.0.2 Uninitialized Memory Read in Flash Screen Video 2 Decoder