CVE-2026-44898
Description
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_toc_ul() builds a <ul> table-of-contents tree from a list of (level, id, text) tuples. Both the id value (used as href="#<id>") and the text value (used as the visible link label) are inserted into <a> tags via a plain Python format string — with no HTML escaping applied to either value. When heading IDs are derived from user-supplied heading text (the standard use-case for readable slug anchors), an attacker can craft a heading whose text breaks out of the href="#..." attribute context, injecting arbitrary HTML tags including <script> blocks directly into the rendered TOC. This vulnerability is fixed in 3.2.1.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| mistune_project | mistune | {"endExcluding":"3.2.1"} | 3.2.1 |
References
- https://github.com/lepture/mistune/security/advisories/GHSA-6269-cqxg-mhhv
- https://github.com/lepture/mistune/commit/04880a0
- https://github.com/lepture/mistune
- https://github.com/lepture/mistune/releases/tag/v3.2.1
- https://www.suse.com/security/cve/CVE-2026-44898.html
- https://github.com/advisories/GHSA-6269-cqxg-mhhv
CWEs
CWE-79
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.