Is CVE-2026-45339 actively exploited?

No active exploitation of CVE-2026-45339 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-45339 be exploited remotely?

Yes. CVE-2026-45339 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-45339?

CVE-2026-45339 has a CVSS score of 6.5 (MEDIUM).

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MEDIUM

CVE-2026-45339

CWE-863Published: May 15, 2026· Updated: May 19, 2026

6.5

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:7.4th

Official 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.

NVD Source

Technical Analysis

CVE-2026-45339 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires high privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 6.5.