CVE-2026-120251

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    CVE-2026-120251

    Published: 1 Nov 2026Last Modified: 8 Nov 2026

    Summary: imagecodecs 2026.3.6 through 2026.10.10 Infinite Loop via ccittfax4_decode()

    Details: imagecodecs 2026.3.6 through 2026.10.10 contains an infinite loop vulnerability in ccitt_fax4_decode_size() that allows attackers to hang the calling process by supplying a crafted CCITT Group 4 stream. Attackers can provide an 8-byte G4 stream lacking EOFB to ccittfax4_decode() or the numcodecs Ccittfax4 codec, consuming full CPU until the process is killed.

    References: https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/120xxx/CVE-2026-120251.json, https://nvd.nist.gov/vuln/detail/CVE-2026-120251, https://www.vulncheck.com/advisories/imagecodecs-2026.3.6-through-2026.10.10-infinite-loop-via-ccittfax4-decode, https://github.com/cgohlke/imagecodecs/issues/158, https://github.com/cgohlke/imagecodecs, https://github.com/cgohlke/imagecodecs/blob/v2026.10.10/3rdparty/ccitt/ccitt.c#L1449

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- f47e63c4fffe44d45dca22757eafa6ec869d5bd9
    Fixed -None

    Affected versions

    v2026.10.10

    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