PT-2026-56513 · Lepture · Mistune

Published 2026-07-08 · Updated 2026-07-08 · CVE-2026-59930

NVD

CVSS v3.1

4.3

Medium

Base vector

AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

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.

Fix

Insufficient Verification of Data Authenticity

Weakness Enumeration

CWE-345

CWE-1284

Related Identifiers

CVE-2026-59930

Affected Products

Mistune

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2026-59930 · Security Note
• https://github.com/lepture/mistune/releases/tag/v3.3.0 · Note
• https://github.com/lepture/mistune/commit/c4093c4742ed0d10d9332fb8edb455869b7b581b · Note
• https://github.com/lepture/mistune/security/advisories/GHSA-2hm2-hc3v-44h9 · Note