Vulnerability · Published May 15, 2026 · Assigned by GitHub_M

CVE-2026-44556Open WebUI: responses passthrough endpoint lacks access control authorization

High 7.1

In plain English

A high-severity improper access control in open-webui from open-webui. There are no confirmed reports of exploitation so far. 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)7.1High

Exploit odds (30 days)0.3%top 76.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

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, the /responses endpoint in the OpenAI router accepts any authenticated user and forwards requests directly to upstream LLM providers without enforcing per-model access control. While the primary chat completion endpoint (generate_chat_completion) checks model ownership, group membership, and AccessGrants before allowing a request, the /responses proxy only validates that the user has a valid session via get_verified_user. This allows any authenticated user to interact with any model configured on the instance by sending a POST request to /api/openai/responses with an arbitrary model ID. This vulnerability is fixed in 0.9.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	open-webui	0.9.0	GHSA-hp5m-24vp-vq2q
PyPI	open-webui	0.9.0	PYSEC-2026-2734

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	< 0.9.0

Weakness: CWE-284, CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-hp5m-24vp-vq2q x_refsource_CONFIRM