PYSEC-2026-3654 pymdown-extensions: exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

Summary Four inline processors in pymdown-extensions contain regular expressions with exponential backtracking. A single untrusted Markdown line under 50 bytes drives markdown.markdown into unbounded CPU on the rendering thread seconds at 45 bytes, growing exponentially with each added character...