Description
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, render_toc_ul() builds a
- table-of-contents tree from a list of (level, id, text) tuples. Both the id value (used as href="#") and the text value (used as the visible link label) are inserted into 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 blocks directly into the rendered TOC. This vulnerability is fixed in 3.2.1.
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| mistune | 3.2.0 | 3.2.1 |
| unknown | — | — |
References
Similar Threats
- Unknown DEBIAN-CVE-2026-44708
- Unknown DEBIAN-CVE-2026-44896
- Unknown DEBIAN-CVE-2026-44897
- Unknown DEBIAN-CVE-2026-44899
- Unknown UBUNTU-CVE-2026-44896
Exploit Protection
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