{"id":"CVE-2026-86000","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, the selector parser in src/soupsieve/css_parser.py defines IDENTIFIER with adjacent quantified groups over overlapping character classes, and V…","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"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T16:18:16.757","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-86000","references":[{"url":"https://github.com/facelessuser/soupsieve/commit/ce44e4996e6632871c18cdd7a7fb641be8ef34ef","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-gjv8-xp57-g29c","label":"security-advisories@github.com"},{"url":"https://github.com/facelessuser/soupsieve/security/advisories/GHSA-gjv8-xp57-g29c","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86000.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-86000"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-86000"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86000"},{"url":"https://github.com/advisories/GHSA-gjv8-xp57-g29c"},{"url":"https://github.com/facelessuser/soupsieve"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2536121"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat","ghsa","pip","osv"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-17T15:45:31.018009Z"},"ingestedAt":"2026-09-17T16:21:47.714Z","scores":{"nvd":5.3,"vendor":5.9,"ghsa":5.3,"osv":5.3},"aliases":["GHSA-gjv8-xp57-g29c"],"ecosystem":"pip","patched":["soupsieve 2.9.0"],"epss":0.00441,"epssPercentile":0.37601,"slug":"CVE-2026-86000","body":"## Overview\n\nSoup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.9, the selector parser in src/soupsieve/css_parser.py defines IDENTIFIER with adjacent quantified groups over overlapping character classes, and VALUE embeds IDENTIFIER for attribute selectors. When an attacker-controlled selector contains a long identifier or unquoted attribute-value run followed by input that makes the overall match fail, the regular expression engine explores quadratically many splits between the overlapping groups. User-controlled selectors can reach this path through soupsieve.compile(), soupsieve.select(), or BeautifulSoup.select(), while applications using only hard-coded selectors are unaffected. The resulting CPU consumption can hold the Python GIL, exhaust application workers, and stall a service; successful plain identifier matches are linear, and the issue does not cause 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## 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-2026-86000.json)\n\n## Package advisory (CVE-2026-86000)\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-gjv8-xp57-g29c","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}