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

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes quadratic work in src/mistune/blockparser.py and the reflinks environment dictionary handling, allowing denial of service...

CVE-2026-59925 inline_parser: quadratic-time parsing on long runs of `**x**` and `***x***` emphasis pairs

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/inlineparser.py because the parser scans forward for matching close markers from...

CVE-2026-33079

A flaw was found in Mistune, a Markdown parser. This vulnerability, known as Regular Expression Denial of Service ReDoS, exists in the LINKTITLERE regular expression. A remote attacker can exploit this by providing specially crafted Markdown input, which causes the regular expression engine to...