TI-2026-83568 Aliases CVE-2026-120243 GHSA-hcx6-ffr8-ff2w

Stack memory leak in FFmpeg G2M decoder via Kempf palette

LOW 29CWE-457Published 2026-11-01 · Updated 2026-11-06

Key facts

Attack vector: Local
Privileges required: None
User interaction: Passive
Attack complexity: Low
Attack requirements: None
Impact type: Information disclosure
Confidentiality · integrity · availability: High · None · None
Fix status: Deferred Red Hat: fix deferred

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-457 and the CVSS impact.

Summary

FFmpeg from 2.0 through 9.0.2 contains a use of uninitialized variable (CWE-457) in its Go2Meeting decoder. Out-of-range palette indices make the decoder copy uninitialized stack bytes into decoded output, which can expose pointers or stack guards. A local attacker with no privileges can leak this stack memory if a user opens a crafted G2M3 or G2M4 file.

Written with Claude Haiku 5.5 from the sources below · 2026-11-01

Description from the CNA

FFmpeg 2.0 through 9.0.2 contains a use of uninitialized variable vulnerability in the Go2Meeting decoder that allows attackers to leak stack memory through out-of-range palette indices. Attackers can craft a G2M3/G2M4 stream with a short Kempf palette so kempf_restore_buf() copies uninitialized stack bytes, including pointers or stack guards, into decoded output.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00124 2nd percentileScored 2026-11-07

Fix Deferred Red Hat: fix deferred

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
FFmpeg	FFmpeg	2.0 – 9.0.2	—	No fix listed	CNA

FFmpeg VendorFFmpeg Affected 2.0 – 9.0.2 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:ffmpeg:ffmpeg::::::::	—	—	FFmpeg

cpe:2.3:a:ffmpeg:ffmpeg:*:*:*:*:*:*:*:* Versions — — ·FFmpeg

Remediation

The sources list no fixed version for FFmpeg. Red Hat lists no available fix for Red Hat Enterprise Linux AI (RHEL AI) 3 and Red Hat OpenShift AI (RHOAI).

Written with Claude Haiku 5.5 from the sources below · 2026-11-01

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux AI (RHEL AI) 3	Affected	No fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)	Affected	No fix yet: Fix deferred

Timeline

2026-11-01 Threatist record created from CVE-2026-120243
2026-11-01 Alias added: GHSA-hcx6-ffr8-ff2w
2026-11-01 Affected versions changed · Red Hat
2026-11-01 CVSS score added · Red Hat
2026-11-02 Priority changed: MEDIUM → LOW
2026-11-06 CISA SSVC decision points changed

References

Patch 1

https://github.com/FFmpeg/FFmpeg/commit/edad2d0dafcf44fa315eab716fd0183ce808053b

Other 3

TI-2025-19015 FFmpeg git-master before commit d5873b was discovered to contain a memory leak in the component libavutil/iamf.c. CVSS 3.1HIGH 8.8
TI-2024-21238 FFmpeg 7.0 contains a heap-buffer-overflow at libavfilter/vf_tiltandshift.c:189:5 in copy_column. CVSS 3.1HIGH 8.4
TI-2023-06050 Ffmpeg: null pointer dereference in ffmpeg hls parsing CVSS 3.1HIGH 7.5
TI-2023-28420 Buffer Overflow vulnerability in Ffmpeg v.N113007-g8d24a28d06 allows a local attacker to… CVSS 3.1HIGH 8.0
TI-2023-27357 FFmpeg v.n6.1-3-g466799d4f5 allows a heap-based buffer overflow via the… CVSS 3.1HIGH 8.0
TI-2023-27044 Buffer Overflow vulnerability in FFmpeg version n6.1-3-g466799d4f5, allows a local… CVSS 3.1HIGH 8.0

See all 538 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences