CVE-2026-59922

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugins/formatting.py when the strikethrough, mark, or insert plugin scans for matching markers from each possible start position, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/lepture/mistune/commit/96d0f57f8fe9eeb06bb4cff521962a27d7c402e7	Patch
https://github.com/lepture/mistune/releases/tag/v3.3.0	Release Notes
https://github.com/lepture/mistune/security/advisories/GHSA-c8j7-8cv4-2xmq	Exploit Vendor Advisory
https://github.com/lepture/mistune/security/advisories/GHSA-c8j7-8cv4-2xmq	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-07-08 17:17

Updated : 2026-07-09 19:36

NVD link : CVE-2026-59922

Mitre link : CVE-2026-59922

CVE.ORG link : CVE-2026-59922

JSON object : View

Products Affected

mistune_project

mistune

CWE

CWE-407

Inefficient Algorithmic Complexity

CWE-1333

Inefficient Regular Expression Complexity

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