PT-2026-56509 · Lepture · Mistune

Published 2026-07-08 · Updated 2026-07-08 · CVE-2026-59923

Mitre

CVSS v3.1

6.1

Medium

Base vector

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

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, HTMLRenderer.safe url() does not block percent-encoded javascript URIs, allowing attacker-supplied Markdown links or images to bypass URL protections and execute script in rendered HTML. This issue is fixed in version 3.3.0.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-59923

Affected Products

Mistune

References · 4

• 🔥 https://github.com/lepture/mistune/security/advisories/GHSA-8c25-4j27-2rv3 · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-59923 · Security Note
• https://github.com/lepture/mistune/releases/tag/v3.3.0 · Note
• https://github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc · Note