p PatchFirst

CVE-2026-59922

CVE-2026-59922 · Mistune plugins/formatting: quadratic-time parsing on long runs of `~~x~~`, `==x==`, and `^^x^^` markers (strikethrough / mark / insert)

This page contains facts from public vulnerability sources. Check the original advisory before updating.

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough, mark, or insert plugin scans for matching markers from each possible start position, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.

CVSS 7.5 · High · EPSS 0.6% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • mistune

    Versions
    • < 3.3.0: Affected

    No fix published

  • mistune Debian:13

    Versions
    • 3.1.3-1
    • 3.1.4-1
    • 3.3.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune Debian:14

    Versions
    • 3.1.3-1
    • 3.1.4-1
    • 3.3.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune PyPI

    Versions
    • 0.1.0
    • 0.2.0
    • 0.3.0
    • 0.3.1
    • 0.4
    • 0.4.1
    • 0.5
    • 0.5.1
    • 0.6
    • 0.7
    • 0.7.1
    • 0.7.2
    • 0.7.3
    • 0.7.4
    • 0.8
    • 0.8.1
    • 0.8.2
    • 0.8.3
    • 0.8.4
    • 2.0.0
    • 2.0.0a1
    • 2.0.0a2
    • 2.0.0a3
    • 2.0.0a4
    • 2.0.0a5
    • 2.0.0a6
    • 2.0.0rc1
    • 2.0.1
    • 2.0.2
    • 2.0.3
    • 2.0.4
    • 2.0.5
    • 2.1.0
    • 3.0.0
    • 3.0.0a1
    • 3.0.0a2
    • 3.0.0a3
    • 3.0.0rc1
    • 3.0.0rc2
    • 3.0.0rc3
    • 3.0.0rc4
    • 3.0.0rc5
    • 3.0.1
    • 3.0.2
    • 3.1.0
    • 3.1.1
    • 3.1.2
    • 3.1.3
    • 3.1.4
    • 3.2.0
    • 3.2.1
    Affected ranges
    • ECOSYSTEM: < 3.3.0

    Update to 3.3.0

  • mistune Ubuntu:16.04:LTS

    Versions
    • 0.6-2
    • 0.7.1-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune Ubuntu:18.04:LTS

    Versions
    • 0.7.4-1
    • 0.8-1
    • 0.8.1-1
    • 0.8.3-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune Ubuntu:20.04:LTS

    Versions
    • 0.8.4-1
    • 0.8.4-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune Ubuntu:22.04:LTS

    Versions
    • 0.8.4-4
    • 0.8.4-5
    • 2.0.0-1+really0.8.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune Ubuntu:24.04:LTS

    Versions
    • 2.0.4-2
    • 3.0.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune Ubuntu:25.10

    Versions
    • 3.0.2-2
    • 3.1.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune Ubuntu:26.10

    Versions
    • 3.1.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mistune Ubuntu:26.04:LTS

    Versions
    • 3.1.3-1
    • 3.1.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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