CVE-2026-120246

EUVD-2026-114743
FFmpeg 4.4 through 9.0.2 contains a use of uninitialized variable vulnerability in the CDXL decoder that leaks stack memory into decoded pixels via unfilled HAM palette entries. Attackers can craft a type-0 CDXL file whose HAM pixels select unfilled new_palette entries in cdxl_decode_ham8() or cdxl_decode_ham6(), exposing stack bytes and pointer fragments in the BGR24 output.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
5.5 MEDIUM
LOCAL
LOW
NONE
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 2.09%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
ffmpegffmpeg
4.4 ≤
𝑥
≤ 9.0.2
CNA
Debian logo
Debian Releases
Debian Product
Codename
ffmpeg
bookworm
vulnerable
bookworm (security)
vulnerable
forky
vulnerable
sid
vulnerable
trixie
vulnerable
trixie (security)
vulnerable
Common Weakness Enumeration
References
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24856
https://github.com/FFmpeg/FFmpeg
https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/cdxl.c#L226-L229
https://github.com/FFmpeg/FFmpeg/commit/47313ad3f9f33b892384b976fb7c09b3c85fd74e
https://www.vulncheck.com/advisories/ffmpeg-4.4-through-9.0.2-uninitialized-memory-disclosure-via-cdxl-ham-decoder