Parser Vulnerability in Open WebUI Affects AI Platform
CVE-2026-59220

6.5MEDIUM

Key Information:

Vendor

Open-webui

Status
Open-webui
Vendor
CVE Published:
9 July 2026

What is CVE-2026-59220?

The Open WebUI platform, a self-hosted AI solution, has a vulnerability that arises from the way it handles regular expressions in its backend. Specifically, the SKILL_MENTION_RE and strip_re patterns can lead to execution issues when an authenticated user sends a chat message containing malformed skill mentions, resulting in overlapping quantifiers. This can trigger significant performance degradation through quadratic backtracking, ultimately blocking the asyncio event loop. This issue has been addressed in version 0.10.0.

Affected Version(s)

open-webui >= 0.9.2, < 0.10.0

References

https://github.com/open-webui/open-webui/security/advisor...
x_refsource_CONFIRM
https://github.com/open-webui/open-webui/commit/61a267221...
x_refsource_MISC
https://github.com/open-webui/open-webui/releases/tag/v0....
x_refsource_MISC

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.