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CVE-2026-76098

CVE-2026-76098 · Mistune has Denial of Service — RecursionError via Excessive Emphasis Markers in Markdown

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

Mistune is a Python Markdown parser with renderers and plugins. Versions 3.3.0 through 3.3.2 are vulnerable to DoS through deeply nested tokens. HTML rendering creates deeply nested emphasis tokens from consecutive asterisk characters, and recursive rendering in HTMLRenderer.render_token() can exceed Python's recursion limit and raise RecursionError, allowing crafted Markdown to crash a parsing process. This issue is fixed in version 3.3.3

CVSS 7.5 · High · EPSS 0.5% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • mistune

    Versions
    • >= 3.3.0, < 3.3.3: Affected

    No fix published

  • mistune Debian:12

    Versions
    • 2.0.4-1
    • 2.0.4-2
    • 3.0.2-1
    • 3.0.2-2
    • 3.1.3-1
    • 3.1.4-1
    • 3.3.4-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    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
    • 3.3.0
    • 3.3.1
    • 3.3.2
    Affected ranges
    • ECOSYSTEM: ≥ 3.3.0, < 3.3.3

    Update to 3.3.3

  • 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: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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