CVE-2026-45339

MEDIUM

Open WebUI: API key endpoint restrictions bypassed via `x-api-key` header — full message processing on restricted endpoints

Title source: cna
STIX 2.1

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.

References (1)

Core 1
Core References

Scores

CVSS v3 6.5
EPSS 0.0003
EPSS Percentile 10.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact total

Details

CWE
CWE-863
Status published
Products (3)
open-webui/open-webui < 0.9.0
openwebui/open_webui < 0.9.0
pypi/open-webu 0 - 0.9.0PyPI
Published May 15, 2026
Tracked Since May 16, 2026