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

{
    "lastseen": "",
    "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.",
    "published": "2026-05-15T19:46:17.750Z",
    "modified": "2026-05-15T19:46:17.750Z",
    "type": "cve",
    "title": "Open WebUI: responses passthrough endpoint lacks access control authorization",
    "source": "GitHub_M",
    "references": "https://github.com/open-webui/open-webui/security/advisories/GHSA-hp5m-24vp-vq2q",
    "id": "CVE-2026-44556",
    "bulletinFamily": "",
    "cwe": [
        "CWE-284",
        "CWE-862"
    ],
    "cvelist": null,
    "sourceData": "open-webui open-webui < 0.9.0",
    "sourceHref": "",
    "cvss": {
        "score": 7.1,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "open-webui",
    "version": "< 0.9.0",
    "vendor": "open-webui",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
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    "ai_score": 0
}