CVE-2026-59926 — Mistune: XSS via unescaped class option in Admonition directive
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…
Published: 2026-07-08 · CVSS: 5.3 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7