CVE WatchJul 9, 2026

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 ar

CVSS

7.5

High

EPSS

0.4%

p29

KEV

—

Exploit Today

0-100

Published: Jul 8, 2026 · Last modified: Jul 9, 2026 · CWE-407 · CWE-1333

EPSS · 30d

0.3%EPSS · 30 days0.4%

2026-07-092026-07-21

Technical description

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.

Official references

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