Vulnerability · Published May 15, 2026 · Assigned by GitHub_M

CVE-2026-45339Open WebUI: API key endpoint restrictions bypassed via `x-api-key` header — full message processing on restricted endpoints

Medium 6.5

In plain English

A medium-severity incorrect authorization in open-webui from open-webui. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.3%top 76.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	open-webui	0.9.0	GHSA-57q6-fvp4-pqmm
PyPI	open-webui	0.9.0	PYSEC-2026-3543

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	< 0.9.0

Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

References

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