{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-44555",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-05-06T20:59:00.594Z",
        "datePublished": "2026-05-15T19:48:35.352Z",
        "dateUpdated": "2026-05-15T20:21:22.063Z"
    },
    "containers": {
        "cna": {
            "title": "Open WebUI: Base Model Routing Bypasses Access Control via Model Chaining",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-862",
                            "lang": "en",
                            "description": "CWE-862: Missing Authorization",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "LOW",
                        "baseScore": 7.6,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "HIGH",
                        "integrityImpact": "LOW",
                        "privilegesRequired": "LOW",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/open-webui/open-webui/security/advisories/GHSA-9vvh-qmjx-p4q8",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-9vvh-qmjx-p4q8"
                }
            ],
            "affected": [
                {
                    "vendor": "open-webui",
                    "product": "open-webui",
                    "versions": [
                        {
                            "version": "< 0.9.0",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-05-15T19:48:35.352Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, Open WebUI supports model composition via base_model_id: a user-defined model (e.g., \"Cheap Assistant\") can reference an existing base model (e.g., \"gpt-4-turbo-restricted\") that provides the actual inference capability. When a user queries the composed model, the access control pipeline verifies the user has access to the composed model but never re-verifies access to the chained base model. Additionally, the model creation and import endpoints accept arbitrary base_model_id values without checking that the caller has access to that base model. Combined, this allows any user with the default model creation permission to create a model that chains to a restricted base model — and then invoke it, causing the server to dispatch the request to the restricted base model using the admin-configured API key. This vulnerability is fixed in 0.9.0."
                }
            ],
            "source": {
                "advisory": "GHSA-9vvh-qmjx-p4q8",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-9vvh-qmjx-p4q8",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-05-15T20:21:00.262151Z",
                                "id": "CVE-2026-44555",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-05-15T20:21:22.063Z"
                }
            }
        ]
    }
}