{"id":"CVE-2026-126191","title":"Soup Sieve: Exponential ReDoS in selector compilation via \\9-run in CSS_ESCAPES/IDENTIFIER","summary":"Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 3.0, the CSS_ESCAPES and IDENTIFIER regular-expression subpatterns can backtrack exponentially on runs of ambiguous digit escapes in an attribute-na…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-1333"],"vendor":"facelessuser","product":"soupsieve","affected":["soupsieve < 3.0"],"published":"2026-11-12","updated":"2026-11-12","sourceUpdated":"2026-11-12T16:57:01.566Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-126191","references":[{"url":"https://github.com/facelessuser/soupsieve/security/advisories/GHSA-6655-6qjp-jx7x","label":"https://github.com/facelessuser/soupsieve/security/advisories/GHSA-6655-6qjp-jx7x"},{"url":"https://github.com/facelessuser/soupsieve/pull/300","label":"https://github.com/facelessuser/soupsieve/pull/300"},{"url":"https://github.com/facelessuser/soupsieve/commit/dbfa2854ff31a863326bd6660d4e55c6f068db9e","label":"https://github.com/facelessuser/soupsieve/commit/dbfa2854ff31a863326bd6660d4e55c6f068db9e"},{"url":"https://github.com/facelessuser/soupsieve/releases/tag/3.0","label":"https://github.com/facelessuser/soupsieve/releases/tag/3.0"}],"tags":["cve.org"],"ingestedAt":"2026-11-12T17:51:14.505Z","slug":"CVE-2026-126191","body":"## Overview\n\nSoup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 3.0, the CSS_ESCAPES 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 failure occurs during selector compilation through soupsieve.compile() or Beautiful Soup select() before SELECTOR_LIMIT is applied, so an application that accepts untrusted selector strings can have a worker stalled by a short input. This issue is fixed in version 3.0.\n\n## Affected\n\n- `soupsieve < 3.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}