FFmpeg through 9.0.2 contains an information disclosure vulnerability in decode_mvc2() in libavcodec/mvcdec.c that leaks uninitialized stack memory through unchecked palette indices. Attackers can supply a crafted MVC2 stream declaring few colors but referencing higher palette indices, copying process stack contents into decoded RGB frames.
https://github.com/FFmpeg/FFmpeg/commit/3a5eb948e76dc6390e4b3cff7becf84bc492b7af
https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/mvcdec.c#L141
https://github.com/FFmpeg/FFmpeg
Published: 2026-11-09
Updated: 2026-11-10
Base Score: 2.1
Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:N/A:N
Severity: Low
Base Score: 3.3
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Severity: Low
Base Score: 4.8
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00128