CVE-2026-45339

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

State: Published
Severity: 6.5 Medium
Published: May 15, 2026
Updated: May 19, 2026
Reserved: May 11, 2026

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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.

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N	GitHub_M

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
open-webuiopen-webui	< 0.9.0Affected

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-57q6-fvp4-pqmm

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