CVE-2026-59925

EUVD-2026-42335 · Published Jul 8, 2026

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, long sequences of well-formed double-asterisk or triple-asterisk emphasis pairs around a character cause quadratic work in src/mistune/inline_parser.py because the parser scans forward for matching close markers from every potential opening run, allowing denial of service in default Mistune parsing. This issue is fixed in version 3.3.0.

Technologies

Mistune_Project Mistune

Weaknesses

CWE-407CWE-1333

CVSS scores

v3.17.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

MITRE ATT&CK

Inferred

Where this vulnerability fits in an attack

ReconImpact

Initial Access

T1190Exploit Public-Facing Application

References

https://github.com/lepture/mistune/security/advisories/GHSA-4j32-57v6-6g45
https://github.com/lepture/mistune/commit/5de41fb8e527004dbc363e047a3c380c9288c74f
https://github.com/lepture/mistune/releases/tag/v3.3.0

Potentially impacted assets

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