CVE-2026-59929: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in lepture mistune
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.
CVE-2026-59929: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in lepture mistune
Description
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 v3.1
Score 6.1medium
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-07T18:20:06.126Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4e7ad5c9d9e3dbe36a7dfd
Added to database: 07/08/2026, 16:29:09 UTC
Last updated: 07/08/2026, 16:29:09 UTC
Views: 1
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