{"id":"CVE-2026-59220","aliases":["GHSA-ffpj-xv5c-p3gw","PYSEC-2026-3596"],"url":"https://o3.security/vulnerability/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 <$skillId|label> skill mentions with overlapping quantifiers, allowing an authenticated chat message containing <$ without a closing > to trigger quadratic backtracking and block the asyncio event loop. This issue is fixed in version 0.10.0.","published":"2026-07-09T16:09:41.127Z","modified":"2026-08-12T03:51:08.705571056Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.00573,"percentile":0.45243,"asOf":"2026-09-07"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"open-webui","fixedVersion":"0.10.0"}],"fix":{"url":"https://github.com/open-webui/open-webui/commit/61a26722155ec6ee1b629cf8dfcf975098c18331","label":"open-webui/open-webui@61a2672"},"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:08.705571056Z"}}