CVE Catalog

CVE-2026-59220

MediumCVSS 6.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.32%

24th percentile - higher than 24% of all known CVEs

Summary

A vulnerability in Open WebUI before version 0.10.0 allowed a ReDoS (Regular Expression Denial of Service) attack by sending a specially crafted chat message containing <$ without a closing >. The SKILL_MENTION_RE and strip_re regular expressions in backend/open_webui/utils/middleware.py caused quadratic backtracking, blocking the asyncio event loop.

Risk Assessment

An authenticated user can cause a denial of service (DoS) by blocking the asyncio event loop, making the AI platform unavailable to all other users.

Recommendation

Immediately update Open WebUI to version 0.10.0 or later, which includes a fix for the ReDoS vulnerability.

Other vulnerabilities in Open WebUI

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS