Bug 2498149 (CVE-2026-59926) - CVE-2026-59926 mistune: Mistune: Cross-Site Scripting via unescaped HTML class attribute in Admonition directive
Summary: CVE-2026-59926 mistune: Mistune: Cross-Site Scripting via unescaped HTML clas...
Keywords:
Status: NEW
Alias: CVE-2026-59926
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-08 17:02 UTC by OSIDB Bzimport
Modified: 2026-07-09 15:16 UTC (History)
13 users (show)

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Description OSIDB Bzimport 2026-07-08 17:02:05 UTC 
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.
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