CVE-2026-59929

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the safe_url filter in src/mistune/renderers/html.py blocks only javascript:, vbscript:, file:, and data: schemes, allowing legacy or chained schemes such as feed:, view-source:, jar:, livescript:, mocha:, ms-its:, mk:, and res: to reach rendered href and src attributes and potentially execute script in affected user agents. This issue is fixed in version 3.3.0.

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/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc	Patch
https://github.com/lepture/mistune/releases/tag/v3.3.0	Release Notes
https://github.com/lepture/mistune/security/advisories/GHSA-qfrw-5rxm-mhh2	Exploit Third Party Advisory

Configurations

Configuration 1 (hide)

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

History

25 Oct 2026, 17:10

Type	Values Removed	Values Added
Summary		(es) Mistune es un analizador de Markdown de Python con renderizadores y complementos. Antes de la 3.3.0, el filtro safe_url en src/mistune/renderers/html.py bloquea solo los esquemas javascript_disabled: , vbscript:, file: y data:, permitiendo que esquemas heredados o encadenados como feed:, view-source:, jar:, livescript:, mocha:, ms-its:, mk: y res: alcancen los atributos href y src renderizados y potencialmente ejecuten scripts en agentes de usuario afectados. Este problema está solucionado en la versión 3.3.0.

Information

Published : 2026-07-08 17:17

Updated : 2026-10-25 17:10

NVD link : CVE-2026-59929

Mitre link : CVE-2026-59929

CVE.ORG link : CVE-2026-59929

JSON object : View

Products Affected

mistune_project

mistune

CWE

CWE-79

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

CWE-184

Incomplete List of Disallowed Inputs

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