{"id":"CVE-2026-59220","summary":"Open WebUI: ReDoS in skill-mention regexes causes whole-instance DoS on default config","details":"Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.2 before 0.10.0, the SKILL_MENTION_RE and strip_re regular expressions in backend/open_webui/utils/middleware.py parsed \u003c$skillId|label\u003e skill mentions with overlapping quantifiers, allowing an authenticated chat message containing \u003c$ without a closing \u003e to trigger quadratic backtracking and block the asyncio event loop. This issue is fixed in version 0.10.0.","aliases":["GHSA-ffpj-xv5c-p3gw"],"modified":"2026-07-15T01:49:16.514748564Z","published":"2026-07-09T16:09:41.127Z","database_specific":{"cwe_ids":["CWE-1333"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59220.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/open-webui/open-webui/releases/tag/v0.10.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59220.json"},{"type":"ADVISORY","url":"https://github.com/open-webui/open-webui/security/advisories/GHSA-ffpj-xv5c-p3gw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59220"},{"type":"FIX","url":"https://github.com/open-webui/open-webui/commit/61a26722155ec6ee1b629cf8dfcf975098c18331"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/open-webui/open-webui","events":[{"introduced":"8dae237a0bfdac4b7f55b463b3e2769ea4b94a0b"},{"fixed":"4d2e13cf2bcc451b33bb6374bea4d2163e6cc94c"},{"fixed":"61a26722155ec6ee1b629cf8dfcf975098c18331"}],"database_specific":{"cpe":"cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0.9.2"},{"fixed":"0.10.0"}],"source":["CPE_RANGE","REFERENCES"]}}],"versions":["v0.9.5","v0.9.4","v0.9.3","v0.9.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59220.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}