CVE-2026-59926

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.

CVSS v3 6.1 MEDIUM

6.1^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 2.7

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://github.com/lepture/mistune/commit/a3cb6e5655308797e8be021d6c7b5bab13cbace2	Patch
https://github.com/lepture/mistune/releases/tag/v3.2.1	Release Notes
https://github.com/lepture/mistune/security/advisories/GHSA-g97x-gvcm-x72h	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*

History

09 Jul 2026, 19:38

Type	Values Removed	Values Added
References	~~() https://github.com/lepture/mistune/commit/a3cb6e5655308797e8be021d6c7b5bab13cbace2 -~~	() https://github.com/lepture/mistune/commit/a3cb6e5655308797e8be021d6c7b5bab13cbace2 - Patch
References	~~() https://github.com/lepture/mistune/releases/tag/v3.2.1 -~~	() https://github.com/lepture/mistune/releases/tag/v3.2.1 - Release Notes
References	~~() https://github.com/lepture/mistune/security/advisories/GHSA-g97x-gvcm-x72h -~~	() https://github.com/lepture/mistune/security/advisories/GHSA-g97x-gvcm-x72h - Vendor Advisory
CPE		cpe:2.3:a:mistune_project:mistune::::::::
First Time		Mistune Project Mistune Project mistune
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 6.1

08 Jul 2026, 17:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-08 17:17

Updated : 2026-07-09 19:38

NVD link : CVE-2026-59926

Mitre link : CVE-2026-59926

CVE.ORG link : CVE-2026-59926

JSON object : View

Products Affected

mistune_project

mistune

CWE

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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