CVE-2026-85999 Soup Sieve: Polynomial-time ReDoS (O(n²)) in the whitespace/comment trimming regex `RE_WS_END` (triggers on VALID selectors)

Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.9, selectoriter in src/soupsieve/cssparser.py trims the raw selector with REWSEND, an end-anchored WSC whitespace-and-comment expression used with search, so the regular expression engine retries a greedy...

CVE-2026-85999

CVE-2026-85999 affects Soup Sieve , a CSS selector library used with Beautiful Soup 4, in versions prior to 2.9 . The root cause is a polynomial-time (O(n²)) regular expression in RE_WS_END within selector_iter (src/soupsieve/css_parser.py). An end-anchored whitespace-and-comment expression, used...

EUVD-2026-81690

Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.9, selectoriter in src/soupsieve/cssparser.py trims the raw selector with REWSEND, an end-anchored WSC whitespace-and-comment expression used with search, so the regular expression engine retries a greedy...