CVE-2026-120246
FFmpeg 4.4 through 9.0.2 Uninitialized Memory Disclosure via CDXL HAM Decoder
- State
- Published
- Severity
- 6.8 Medium
- Published
- Nov 1, 2026
- Updated
- Nov 1, 2026
- Reserved
- Oct 31, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 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 | VulnCheck |
| 3.1 | 5.5 Medium | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N | VulnCheck |
Weaknesses
- CWE-457 Use of Uninitialized Variable
Affected Products
| Product | Versions |
|---|---|
FFmpegFFmpeg |
|
References
- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24856issue-tracking
- https://github.com/FFmpeg/FFmpeg/commit/47313ad3f9f33b892384b976fb7c09b3c85fd74epatch
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/cdxl.c#L226-L229technical-description
- https://github.com/FFmpeg/FFmpegproduct
- VulnCheck Advisory: FFmpeg 4.4 through 9.0.2 Uninitialized Memory Disclosure via CDXL HAM Decoderthird-party-advisory
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