Is CVE-2026-59925 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-59925?

CVE-2026-59925 has a CVSS v3 severity of HIGH (7.5).

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CVE-2026-59925

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.