CVE-2026-59926 (GCVE-0-2026-59926)
Vulnerability from cvelistv5 – Published: 2026-07-08 16:16 – Updated: 2026-07-08 19:40
VLAI
EPSS
VEX
Title
Mistune: XSS via unescaped class option in Admonition directive
Summary
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.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-08 17:48 UTC
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/lepture/mistune/security/advis… | x_refsource_CONFIRM |
| https://github.com/lepture/mistune/commit/a3cb6e5… | x_refsource_MISC |
| https://github.com/lepture/mistune/releases/tag/v3.2.1 | x_refsource_MISC |
Impacted products
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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