CVE-2026-59220 — Open WebUI: ReDoS in skill-mention regexes causes whole-instance DoS on default config
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/…
Published: 2026-07-09 · CVSS: 6.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7