# CVE-2026-120243: FFmpeg 2.0 through 9.0.2 Information Disclosure via G2M Kempf Palette

Status: published. Published: 2026-11-01. Updated: 2026-11-06.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/FFmpeg/FFmpeg/commit/edad2d0dafcf44fa315eab716fd0183ce808053b

## Affected products and versions

- FFmpeg / FFmpeg (ffmpeg/ffmpeg): ≥ 2.0; ≤ 9.0.2 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.8 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N; source: CNA: VulnCheck

- CVSS 4.0: 6.8 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.12% as of 2026-11-06; percentile 2.13%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-457

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24858 (CNA: VulnCheck; issue-tracking)

- https://github.com/FFmpeg/FFmpeg/commit/edad2d0dafcf44fa315eab716fd0183ce808053b (CNA: VulnCheck; patch)

- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/g2meet.c#L1040-L1042 (CNA: VulnCheck; technical-description)

- https://github.com/FFmpeg/FFmpeg (CNA: VulnCheck; product)

- https://www.vulncheck.com/advisories/ffmpeg-2.0-through-9.0.2-information-disclosure-via-g2m-kempf-palette (CNA: VulnCheck; third-party-advisory)

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24858 (disclosure@vulncheck.com)

- https://github.com/FFmpeg/FFmpeg (disclosure@vulncheck.com)

- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/g2meet.c#L1040-L1042 (disclosure@vulncheck.com)

- https://github.com/FFmpeg/FFmpeg/commit/edad2d0dafcf44fa315eab716fd0183ce808053b (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/ffmpeg-2.0-through-9.0.2-information-disclosure-via-g2m-kempf-palette (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-120243; retrieved 2026-11-06; source updated 2026-11-06

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-120243; retrieved 2026-11-03; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-120243; retrieved 2026-11-06; source updated Not reported

Revision: adfd0f55f46fdbd7085e0fc79daf4ab56d7906b0b9d38e30d8143327c4650537

Canonical: https://y2.dev/cve/CVE-2026-120243

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