UBUNTU-CVE-2019-25781

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    UBUNTU-CVE-2019-25781

    Published: 29 Oct 2026Last Modified: 5 Nov 2026
    Upstream:
    CVE-2019-25781

    Summary:

    Details: Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.

    References: https://ubuntu.com/security/CVE-2019-25781, https://www.cve.org/CVERecord?id=CVE-2019-25781, https://github.com/Python-Markdown/markdown, https://github.com/Python-Markdown/markdown/blob/b41e0aaf1181f1a8cb200cf5a815aad7c0020d23/markdown/inlinepatterns.py#L1155-L1172, https://github.com/Python-Markdown/markdown/issues/1654, https://github.com/Python-Markdown/markdown/issues/798, https://www.vulncheck.com/advisories/python-markdown-3.0-through-3.11.2-denial-of-service-via-link-bracket-parsing

    Affected packages

    Package

    Name: python-markdown

    Purl: pkg:deb/ubuntu/python-markdown?arch=source&distro=trusty

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    2.3.1-1
    2.3.1-2

    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
    UBUNTU-CVE-2019-25781 | CVE-DB