Open WebUI up to 0.9.x Middleware middleware.py incorrect regex

CVSS Meta Temp Score
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CTI Interest Score
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3.4$0-$5k0.56

Summaryinfo

A vulnerability has been found in Open WebUI up to 0.9.x and classified as problematic. Affected is an unknown function of the file backend/open_webui/utils/middleware.py of the component Middleware. This manipulation causes incorrect regex. This vulnerability appears as CVE-2026-59220. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Open WebUI up to 0.9.x. It has been declared as problematic. Affected by this vulnerability is an unknown part of the file backend/open_webui/utils/middleware.py of the component Middleware. The manipulation with an unknown input leads to a incorrect regex vulnerability. The CWE definition for the vulnerability is CWE-185. The product specifies a regular expression in a way that causes data to be improperly matched or compared. As an impact it is known to affect availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-59220 since 07/02/2026. The exploitation appears to be easy. The attack can be launched remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

Upgrading to version 0.10.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.5
VulDB Meta Temp Score: 3.4

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Incorrect regex
CWE: CWE-185 / CWE-697
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: Open WebUI 0.10.0

Timelineinfo

07/02/2026 CVE reserved
07/09/2026 +7 days Advisory disclosed
07/09/2026 +0 days VulDB entry created
07/09/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-59220 (🔒)
GCVE (CVE): GCVE-0-2026-59220
GCVE (VulDB): GCVE-100-377233

Entryinfo

Created: 07/09/2026 19:06
Changes: 07/09/2026 19:06 (53)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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