CVE-2021-27291

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    CVE-2021-27291

    Published: 17 Mar 2021Last Modified: 9 Sept 2026

    Summary:

    Details: In pygments 1.1+, fixed in 2.7.4, the lexers used to parse programming languages rely heavily on regular expressions. Some of the regular expressions have exponential or cubic worst-case complexity and are vulnerable to ReDoS. By crafting malicious input, an attacker can cause a denial of service.

    References: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/, https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/, https://lists.debian.org/debian-lts-announce/2021/03/msg00024.html, https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html, https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html, https://www.debian.org/security/2021/dsa-4878, https://www.debian.org/security/2021/dsa-4889, https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14, https://gist.github.com/b-c-ds/b1a2cc0c68a35c57188575eb496de5ce

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- f534f990331df660f5a5ea6947943e184672ac51
    Fixed -4d555d0fffc914a2a4ac9874416cdaaf8f8c9e74

    Affected versions

    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
    CVE-2021-27291 | CVE-DB