CVE-2026-59929 — Security Box Score

CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-59929MEDIUM

lepture mistune — Mistune renderers/html.safe_url: HARMFUL_PROTOCOLS list misses legacy and chained schemes that historically chain to `javascript:` execution

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   R  C  L  L  N    6.1   .0022   13.5     —

AFFECTED
  Product  Versions   Fixed
  mistune  < 3.3.0 –  —

TIMELINE
  Jul 7   Reserved by GitHub_M
  Jul 8   EXPLOIT PUBLISHED — CVE-2026-59929 (lepture mistune). Public exploit reference added.
  Jul 8   Published (CNA: GitHub_M)

CWE-79, CWE-184 · CNA: GitHub_M · CVSS v3.1 · 3 references · NVD status: Analyzed

Description

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the safe_url filter in src/mistune/renderers/html.py blocks only javascript:, vbscript:, file:, and data: schemes, allowing legacy or chained schemes such as feed:, view-source:, jar:, livescript:, mocha:, ms-its:, mk:, and res: to reach rendered href and src attributes and potentially execute script in affected user agents. This issue is fixed in version 3.3.0.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
July 7, 2026	Reserved	Reserved by GitHub_M
July 8, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-59929 (lepture mistune). Public exploit reference added.
July 8, 2026	Published	Published (CNA: GitHub_M)

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
lepture	mistune	—	< 3.3.0	—

Weaknesses

CWE-79 · CWE-184

References (3)

https://github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc [Patch]
https://github.com/lepture/mistune/releases/tag/v3.3.0 [Release Notes]
https://github.com/lepture/mistune/security/advisories/GHSA-qfrw-5rxm-mhh2 [Exploit, Third Party Advisory]

Authoritative record: CVE-2026-59929 at cve.org

Vendors: lepture

Weaknesses: CWE-79 · CWE-184

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-59929 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.