CVE-2026-126191

Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 3.0, the CSSESCAPES and IDENTIFIER regular-expression subpatterns can backtrack exponentially on runs of ambiguous digit escapes in an attribute-name or tag position of an otherwise valid selector. The failur...

CVE-2026-126191

The Soup Sieve CSS selector library, used with Beautiful Soup 4 , is vulnerable to exponential regular-expression backtracking in versions prior to 3.0 . The vulnerability exists because the CSS_ESCAPES and IDENTIFIER subpatterns can backtrack exponentially when processing ambiguous digit escapes...