CVE-2026-59220 | THREATINT

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.

PUBLISHED Reserved 2026-07-02 | Published 2026-07-09 | Updated 2026-07-09 | Assigner GitHub_M

MEDIUM: 6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem types

CWE-1333: Inefficient Regular Expression Complexity

Product status

>= 0.9.2, < 0.10.0

affected

References

github.com/...-webui/security/advisories/GHSA-ffpj-xv5c-p3gw exploit

github.com/...-webui/security/advisories/GHSA-ffpj-xv5c-p3gw

github.com/...ommit/61a26722155ec6ee1b629cf8dfcf975098c18331

github.com/open-webui/open-webui/releases/tag/v0.10.0

cve.org (CVE-2026-59220)

nvd.nist.gov (CVE-2026-59220)

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