{"id":"CVE-2026-85999","title":"Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4","summary":"Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.9, selector_iter in src/soupsieve/css_parser.py trims the raw selector with RE_WS_END, an end-anchored WSC whitespace-and-comment expression used …","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","cwe":["CWE-400","CWE-1333"],"vendor":"facelessuser","product":"soupsieve","affected":["soupsieve < 2.9"],"patched":["soupsieve 2.9.0"],"published":"2026-09-17","updated":"2026-09-23","sourceUpdated":"2026-09-23T18:12:04.247","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-85999","references":[{"url":"https://github.com/facelessuser/soupsieve/commit/cf198fcddc9230f06ed39f974eba0ce076b85cda","label":"security-advisories@github.com"},{"url":"https://github.com/facelessuser/soupsieve/releases/tag/2.9","label":"security-advisories@github.com"},{"url":"https://github.com/facelessuser/soupsieve/security/advisories/GHSA-j934-xhv5-fg8f","label":"security-advisories@github.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-85999.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-85999"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-85999"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-85999"},{"url":"https://github.com/advisories/GHSA-j934-xhv5-fg8f"},{"url":"https://github.com/facelessuser/soupsieve"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2536116"}],"tags":["nvd","cve.org","csaf","vex","red-hat","ghsa","pip","osv","exploit-available"],"epss":0.00609,"epssPercentile":0.46832,"aliases":["GHSA-j934-xhv5-fg8f"],"ecosystem":"pip","exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-22T16:55:16.479978Z"},"scores":{"nvd":5.3,"vendor":5.9,"cna":5.3},"ingestedAt":"2026-09-17T16:21:47.713Z","slug":"CVE-2026-85999","body":"## Overview\n\nSoup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.9, selector_iter in src/soupsieve/css_parser.py trims the raw selector with RE_WS_END, an end-anchored WSC whitespace-and-comment expression used with search(), so the regular expression engine retries a greedy scan at every starting offset. An attacker-controlled valid selector containing a long internal whitespace run, or a selector containing a long CSS comment run followed by another token, causes quadratic CPU work before tokenization. User-controlled selectors can reach the path through soupsieve.compile() and BeautifulSoup.select(), while applications using only hard-coded selectors are unaffected. This root cause is separate from the IDENTIFIER and VALUE backtracking vulnerability because the cost occurs in RE_WS_END.search during trimming rather than token matching. The resulting CPU consumption can hold the Python GIL, exhaust workers, and stall a service without causing memory corruption or code execution. The issue is fixed in version 2.9.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-85999)\n\nAffected packages:\n\n- `soupsieve < 2.9.0`\n\nPatched in:\n\n- `soupsieve 2.9.0`\n\nSource: https://github.com/advisories/GHSA-j934-xhv5-fg8f\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Exploit Intelligence, Lightspeed Core, Migration Toolkit for Applications 8, OpenShift Lightspeed, Red Hat Ansible Automation Platform 2, Red Hat OpenShift AI (RHOAI), … · no fix planned: Lightspeed Core, Migration Toolkit for Applications 8, OpenShift Lightspeed, Red Hat Ansible Automation Platform 2, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-85999.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":209395,"id":"CVE-2026-85999","ts":1790111560439,"field":"exploit_available","old":"false","new":"true"}]}