GHSA-C8J7-8CV4-2XMQ Mistune plugins/formatting: quadratic-time parsing on long runs of `~~x~~`, `==x==`, and `^^x^^` markers (strikethrough / mark / insert)

Summary Type: Algorithmic-complexity denial of service. A run of N closed pairs xx... or the analogous ==x== for mark, ^^x^^ for insert causes ON² work in the formatting parser. With the strikethrough, mark, or insert plugin enabled, an 8 KB input pegs the CPU for 4 seconds; 16 KB → 17 seconds...

PT-2026-45951

Name of the Vulnerable Software and Affected Versions Python affected versions not specified Description The unicodedata.normalize function can consume excessive CPU time when processing specially crafted Unicode input. This occurs when the input contains long sequences of combining characters wi...