CVE-2026-59220

Description

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.

CVSS Vector

References

• https://github.com/open-webui/open-webui/commit/61a26722155ec6ee1b629cf8dfcf975098c18331
• https://github.com/open-webui/open-webui/releases/tag/v0.10.0
• https://github.com/open-webui/open-webui/security/advisories/GHSA-ffpj-xv5c-p3gw
• https://github.com/open-webui/open-webui/security/advisories/GHSA-ffpj-xv5c-p3gw