CVE-2026-59930

Name	CVE-2026-59930
Description	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
mistune (PTS)	bullseye	0.8.4-4	vulnerable
	bookworm	2.0.4-1	vulnerable
	trixie	3.1.3-1	vulnerable
	forky, sid	3.1.4-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
mistune	source	(unstable)	(unfixed)

Notes

[trixie] - mistune <no-dsa> (Minor issue)
https://github.com/lepture/mistune/security/advisories/GHSA-2hm2-hc3v-44h9
Fixed by: https://github.com/lepture/mistune/commit/c4093c4742ed0d10d9332fb8edb455869b7b581b (v3.3.0)