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

Summary Type: Algorithmic-complexity DoS in core emphasis parsing. A long sequence of well-formed x strong or x strong-emphasis combined pairs causes ON² parser work. Distinct from the bracket-bomb DoS repetition and from the formatting-plugin DoS /==/^^; this one fires on default-config mistune...

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...

PT-2026-56510

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...