CVE-2026-59928

EUVD-2026-42338 · Published Jul 8, 2026

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.

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-ffq3-xpv3-j92q
https://github.com/lepture/mistune/commit/2b04d7ba341c16ac78fe82d3076bdd5c3de87c69
https://github.com/lepture/mistune/releases/tag/v3.3.0

Potentially impacted assets

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