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CVE-2026-44556

HIGHCVSS 7.1/10EPSS 0.31%

Last modified

CVE-2026-44556 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. 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. EPSS estimates a 0.31% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.1/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H

EPSS Probability
0.31%

22.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
OpenwebuiOpen Webui< 0.9.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-44556?
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.
How severe is CVE-2026-44556?
CVE-2026-44556 has a CVSS score of 7.1/10 (HIGH severity). The EPSS model estimates a 0.31% probability of exploitation in the next 30 days.
How do I fix CVE-2026-44556?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-44556?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST