CVE-2026-59928

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes quadratic work in src/mistune/block_parser.py and the ref_links environment dictionary handling, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.

• CWE-407
• CWE-1333

• https://github.com/lepture/mistune/commit/2b04d7ba341c16ac78fe82d3076bdd5c3de87c69Patch
• https://github.com/lepture/mistune/releases/tag/v3.3.0Release Notes
• https://github.com/lepture/mistune/security/advisories/GHSA-ffq3-xpv3-j92qExploit, Third Party Advisory
• https://github.com/lepture/mistune/security/advisories/GHSA-ffq3-xpv3-j92qExploit, Third Party Advisory

Published

Jul 8, 2026

Last Modified

Jul 9, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-59922Mistune is a Python Markdown parser with renderers and plugi…7.5
• CVE-2026-59923Mistune is a Python Markdown parser with renderers and plugi…6.1
• CVE-2026-59924Mistune is a Python Markdown parser with renderers and plugi…5.9
• CVE-2026-59925Mistune is a Python Markdown parser with renderers and plugi…7.5
• CVE-2026-59926Mistune is a Python Markdown parser with renderers and plugi…6.1
• CVE-2026-59927Mistune is a Python Markdown parser with renderers and plugi…5.3
• CVE-2026-59929Mistune is a Python Markdown parser with renderers and plugi…6.1
• CVE-2026-5993A vulnerability was identified in Totolink A7100RU 7.4cu.231…9.8
• CVE-2026-59930Mistune is a Python Markdown parser with renderers and plugi…4.3
• CVE-2026-59931PhpSpreadsheet is a pure PHP library for reading and writing…7.7
• CVE-2026-59932PhpSpreadsheet is a pure PHP library for reading and writing…7.5
• CVE-2026-59933PhpSpreadsheet is a pure PHP library for reading and writing…7.5