CVE-2026-120246

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    CVE-2026-120246

    Published: 1 Nov 2026Last Modified: 7 Nov 2026

    Summary: FFmpeg 4.4 through 9.0.2 Uninitialized Memory Disclosure via CDXL HAM Decoder

    Details: 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.

    References: https://code.ffmpeg.org/FFmpeg/FFmpeg, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/120xxx/CVE-2026-120246.json, https://nvd.nist.gov/vuln/detail/CVE-2026-120246, https://www.vulncheck.com/advisories/ffmpeg-4.4-through-9.0.2-uninitialized-memory-disclosure-via-cdxl-ham-decoder, https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24856, https://github.com/FFmpeg/FFmpeg/commit/47313ad3f9f33b892384b976fb7c09b3c85fd74e, https://github.com/FFmpeg/FFmpeg, https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/cdxl.c#L226-L229

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- c5079bf3bccd24bf8ed45ff47ff4071fd09e9fd8
    Fixed -47313ad3f9f33b892384b976fb7c09b3c85fd74e

    Affected versions

    n9.1-dev

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High