PYSEC-2026-3071 Soup Sieve has Memory Exhaustion via Large Comma-Separated Selector Lists

Summary The CSS selector parser in soupsieve the CSS selector engine for Beautiful Soup 4 allocates unbounded memory when compiling large comma-separated selector lists. An attacker who can supply a crafted CSS selector string to soupsieve.compile or Beautiful Soup's .select / .selectone can caus...