CVE-2026-59926
MEDIUMMistune: XSS via unescaped class option in Admonition directive
Title source: cnaDescription
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.
References (3)
Core 3
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/lepture/mistune/security/advisories/GHSA-g97x-gvcm-x72h
X_Refsource_Misc x_refsource_misc
https://github.com/lepture/mistune/commit/a3cb6e5655308797e8be021d6c7b5bab13cbace2
X_Refsource_Misc x_refsource_misc
https://github.com/lepture/mistune/releases/tag/v3.2.1
Scores
CVSS v4
5.3
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Details
CWE
CWE-79
Status
published
Products (1)
lepture/mistune
< 3.2.1
Published
Jul 08, 2026
Tracked Since
Jul 08, 2026