CVE-2026-86430

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    CVE-2026-86430

    Published: 7 Sept 2026Last Modified: 12 Sept 2026

    Summary: league/commonmark before 2.9.1 Denial of Service via parsing

    Details: league/commonmark versions before 2.9.1 contain multiple denial of service vulnerabilities in fenced code block detection, reference link label lookup, and emphasis delimiter processing that perform super-linear work on crafted input. Attackers can submit specially crafted Markdown with long backtick runs, nested brackets, or delimiter sequences to consume disproportionate CPU time and prevent legitimate requests from completing.

    References: https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86430.json, https://github.com/thephpleague/commonmark/security/advisories/GHSA-j8pm-gj4c-rq4x, https://nvd.nist.gov/vuln/detail/CVE-2026-86430, https://www.vulncheck.com/advisories/league-commonmark-before-2.9.1-denial-of-service-via-parsing

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- c352207aab15706a1ca9c25e5bd30c847899a0c9
    Fixed -73cb188c785abfa7a7bec73487148202968274c6

    Affected versions

    2.9.0

    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-2026-86430 | CVE-DB