{"id":"DEBIAN-CVE-2026-86000","details":"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 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.","modified":"2026-09-19T07:01:09.746549665Z","published":"2026-09-17T16:18:16.757Z","upstream":["CVE-2026-86000"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-86000"}],"affected":[{"package":{"name":"soupsieve","ecosystem":"Debian:12","purl":"pkg:deb/debian/soupsieve?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.2-1","2.4-1","2.4.1-1","2.4.1-2","2.5-1","2.6-1","2.7-1","2.7-2","2.8.1-1","2.8.3-1","2.8.4-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86000.json"}},{"package":{"name":"soupsieve","ecosystem":"Debian:13","purl":"pkg:deb/debian/soupsieve?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.7-1","2.7-2","2.8.1-1","2.8.3-1","2.8.4-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86000.json"}},{"package":{"name":"soupsieve","ecosystem":"Debian:14","purl":"pkg:deb/debian/soupsieve?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.7-1","2.7-2","2.8.1-1","2.8.3-1","2.8.4-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-86000.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}