CVE-2026-45339

What it is

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.

At a glance

Exploitability

Can be exploited over the network with an admin-level account. High risk of data exposure, data tampering.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-15 20:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 10:51 UTC Last updatedMost recent change to the record

Details

Published

2026-05-15 20:16 UTC

Last modified

2026-06-17 10:51 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-863 · Incorrect authorization

Record status

Analyzed

Affected

• Openwebui Open Webui < 0.9.0

Attack profile CVSS 3.1 · 6.5

Attack vector

Network

Complexity

Low

Privileges needed

High

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None