MEDIUM 6.1

PYSEC-2026-2217

Quick fix

PYSEC-2026-2217 — mistune: upgrade to the fixed version with the command below.

pip install --upgrade 'mistune>=3.3.0'

Details

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.

Are you affected?

Enter the version of the package you're using.

Affected packages

PyPI / mistune

Introduced in: 0 Fixed in: 3.3.0

Fix pip install --upgrade 'mistune>=3.3.0'

References

https://github.com/lepture/mistune/releases/tag/v3.3.0 [ADVISORY]
https://github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc [FIX]
https://github.com/lepture/mistune/security/advisories/GHSA-qfrw-5rxm-mhh2 [EVIDENCE]