CVE-2026-59930
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.
- CVSS 3.1
- 4.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 8% of CVEs (scores of 2026-10-25)
- CWEs
- CWE-345, CWE-1284
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mistune_project:mistune
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-2hm2-hc3v-44h9 | PyPI | mistune | <3.3.0 | 3.3.0 |
| PYSEC-2026-2218 | PyPI | mistune | <3.3.0 | 3.3.0 |