CVE-2026-120243

Description

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.

Metrics

CVSS 3.1

5.5 (MEDIUM) Score source: NVD CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS 4.0

6.8 (MEDIUM) Score source: CNA 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

EPSS — exploit probability

0% (percentile: 2) as of 1 November 2026

CWE

CWE-457

References

• https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24858
• https://github.com/FFmpeg/FFmpeg
• https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/g2meet.c#L1040-L1042
• https://github.com/FFmpeg/FFmpeg/commit/edad2d0dafcf44fa315eab716fd0183ce808053b
• https://www.vulncheck.com/advisories/ffmpeg-2.0-through-9.0.2-information-discl…