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.
CVE-2026-44556
HIGHNVD 7.17.1—
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 7.1 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 97% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.1
- CVSS v3
- 7.1
- EG Score
- 7.1(medium)
- EPSS
- 2.8%
- KEV
- Not listed
Published
May 15, 2026
Last Modified
May 19, 2026
References (1)
- security-advisories@githubhttps://github.com/open-webui/open-webui/security/advisories/GHSA-hp5m-24vp-vq2q
Frequently asked(5)
What is CVE-2026-44556?
CVE-2026-44556 is a high vulnerability published on May 15, 2026. 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…
When was CVE-2026-44556 disclosed?
CVE-2026-44556 was first published in the National Vulnerability Database on May 15, 2026, with the most recent update on May 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44556 actively exploited?
CVE-2026-44556 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-44556?
CVE-2026-44556 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-44556?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44556, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-44556
Is Your Infrastructure Affected by CVE-2026-44556?
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