Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mistune Project | Mistune | < 3.3.0 |
Related Weaknesses (CWE)
References
- https://github.com/lepture/mistune/commit/5de41fb8e527004dbc363e047a3c380c9288c7Patch
- https://github.com/lepture/mistune/releases/tag/v3.3.0Release Notes
- https://github.com/lepture/mistune/security/advisories/GHSA-4j32-57v6-6g45ExploitVendor Advisory
FAQ
What is CVE-2026-59925?
CVE-2026-59925 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 ...
How severe is CVE-2026-59925?
CVE-2026-59925 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-59925?
Check the references section above for vendor advisories and patch information. Affected products include: Mistune Project Mistune.