MEDIUM 6.1

PYSEC-2026-2214

Quick fix

PYSEC-2026-2214 — mistune: upgrade to the fixed version with the command below.

pip install --upgrade 'mistune>=3.3.0'

Details

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_admonition() in src/mistune/directives/admonition.py concatenates the Admonition directive :class: option into the HTML class attribute without escaping, allowing attribute injection and cross-site scripting even when HTMLRenderer escape mode is enabled. This issue is fixed in version 3.2.1.

Are you affected?

Enter the version of the package you're using.

Affected packages

PyPI / mistune

Introduced in: 0 Fixed in: 3.3.0

Fix pip install --upgrade 'mistune>=3.3.0'

References

https://github.com/lepture/mistune/releases/tag/v3.2.1 [ADVISORY]
https://github.com/lepture/mistune/security/advisories/GHSA-g97x-gvcm-x72h [ADVISORY]
https://github.com/lepture/mistune/commit/a3cb6e5655308797e8be021d6c7b5bab13cbace2 [FIX]