PT-2026-56510 · Pypi · Mistune

Published 2026-07-08 · Updated 2026-07-08 · CVE-2026-59925

Positive Technologies (AI Summary)

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Mistune versions prior to 3.3.0

Description A denial of service issue exists in the default parsing process. 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.

Recommendations Update to version 3.3.0.

Fix

DoS

Weakness Enumeration

CWE-1333

CWE-407

Related Identifiers

CVE-2026-59925

Affected Products

Mistune

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2026-59925 · Security Note
• https://github.com/lepture/mistune/releases/tag/v3.3.0 · Note
• https://github.com/lepture/mistune/commit/5de41fb8e527004dbc363e047a3c380c9288c74f · Note
• https://github.com/lepture/mistune/security/advisories/GHSA-4j32-57v6-6g45 · Note
• https://twitter.com/infoflowcloud/status/2074933073821524232 · Twitter Post
• https://twitter.com/CVEnew/status/2074931628124578005 · Twitter Post