MEDIUM 4.3

PYSEC-2026-2218

Quick fix

PYSEC-2026-2218 — 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 toc plugin and TableOfContents directive generate heading IDs as predictable toc_N values without slugifying the heading text, allowing attacker-controlled id="toc_N" content to collide with generated anchors and redirect same-page navigation, CSS selectors, or JavaScript handlers. 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/c4093c4742ed0d10d9332fb8edb455869b7b581b [FIX]
https://github.com/lepture/mistune/security/advisories/GHSA-2hm2-hc3v-44h9 [EVIDENCE]