CVE-2026-59928: Mistune block_parser: quadratic-time parsing on long lists of repeated reference-link definitions

Overview

Severity

High (CVSS 7.5)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Status

Not Exploited

Patch Tuesday

2026-Jul

Released

2026-07-11

EPSS Score

0.65% (percentile: 48.3%)

Affected Products (1)

Other

• 21576-17084

Revision History

• 2026-07-11: Information published.