VDB-364244 · CVE-2026-45339 · GHSA-57q6-fvp4-pqmm

open-webui Open WebUI up to 0.8.x API Endpoint /api/v1/messages authorization

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.5	$0-$5k	0.00

Summaryinfo

A vulnerability was found in open-webui Open WebUI up to 0.8.x. It has been declared as problematic. Affected by this issue is some unknown functionality of the file /api/v1/messages of the component API Endpoint. Such manipulation leads to authorization. This vulnerability is traded as CVE-2026-45339. The attack may be launched remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in open-webui Open WebUI up to 0.8.x and classified as problematic. Affected by this issue is some unknown processing of the file /api/v1/messages of the component API Endpoint. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI allows admins to restrict which API endpoints an API key can access. When an API key is restricted from /api/v1/messages, requests using the Authorization: Bearer sk-... header are correctly blocked with 403. However, the same key sent via the x-api-key header bypasses the restriction entirely — the request is authenticated, the model is invoked, and a full response is returned. This vulnerability is fixed in 0.9.0.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-45339 since 05/11/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are needed for exploitation. There are known technical details, but no exploit is available.

Upgrading to version 0.9.0 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

open-webui

Name

Open WebUI

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 4.7
VulDB Temp Score: 4.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authorization
CWE: CWE-863 / CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Open WebUI 0.9.0

Timelineinfo

05/11/2026 CVE reserved
05/16/2026 +5 days Advisory disclosed
05/16/2026 +0 days VulDB entry created
05/16/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: GHSA-57q6-fvp4-pqmm
Status: Confirmed

CVE: CVE-2026-45339 (🔒)
GCVE (CVE): GCVE-0-2026-45339
GCVE (VulDB): GCVE-100-364244

Entryinfo

Created: 05/16/2026 06:26
Changes: 05/16/2026 06:26 (65)
Complete: 🔍
Cache ID: 216::103