CVE-2026-45339

Name: CVE-2026-45339
Creator: NVD / NIST
Published: 2026-05-15T20:16:48.693+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.31%

Last modified Jun 17, 2026

CVE-2026-45339 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.31% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

EPSS Probability

0.31%

22.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-863

Affected Software

Vendor	Product	Versions
Openwebui	Open Webui	< 0.9.0

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-57q6-fvp4-pqmmExploit, Vendor Advisory
https://github.com/open-webui/open-webui/security/advisories/GHSA-57q6-fvp4-pqmmExploit, Vendor Advisory

Timeline

Published: May 15, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-45339?

How severe is CVE-2026-45339?

CVE-2026-45339 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.31% probability of exploitation in the next 30 days.

How do I fix CVE-2026-45339?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-45339?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST