CVE-2026-59220mediumCWE-1333

CVE-2026-59220: medium-severity vulnerability in open-webui

Open WebUI: ReDoS in skill-mention regexes causes whole-instance DoS on default config

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 6.5epss 0.6%
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:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected products
open-webui · open-webui
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