November 14, 2026

CVE Watchtower

CVE-2026-125197FFmpeg FFmpeg

NVD

Vulnerability Summary

FFmpeg through 9.0.2 contains an integer underflow in decode_frame() in libavcodec/lcldec.c that allows attackers to trigger a heap out-of-bounds read via short ZLIB packets with FLAG_MULTITHREAD. Attackers can supply a crafted AVI or MKV file with an LCL video stream whose packet is shorter than 8 bytes, bypassing length clamping to crash the decoding application.
Severity Level
MEDIUM(6.9)
Published Date
Nov 9, 2026
Last Modified
Nov 9, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.14%Probability
Root Weakness (CWE)
CWE-191 ↗
See the MITRE CWE entry for the full definition of this weakness.
CVSS v4.0 Base Metrics — Score 6.9 (MEDIUM)
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
Attack VectorLocal
Attack ComplexityLow
Attack RequirementsNone
Privileges RequiredNone
User InteractionPassive
Confidentiality (Vulnerable System)Low
Integrity (Vulnerable System)None
Availability (Vulnerable System)High
Confidentiality (Subsequent System)None
Integrity (Subsequent System)None
Availability (Subsequent System)None
Show CVSS v3.x metrics (score 6.1)
CVSS v3.1 Base Metrics — Score 6.1 (MEDIUM)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
Attack VectorLocal
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged
ConfidentialityLow
IntegrityNone
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • FFmpeg FFmpeg <= 9.0.2
Patched Versions
  • FFmpeg FFmpeg 9.0.2

What to do

Fix it during your normal patch cycle. No exploitation is confirmed yet.

  1. Check whether you run FFmpeg FFmpeg and which version.
  2. Update to a patched version listed above, then confirm the new version.

Timeline

  • Nov 9, 2026Published
  • Nov 9, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 13, 2026 21:28 UTC