Open WebUI: Redis Cache Keys tool_servers and terminal_servers Missing Instance Prefix Enable Cross-Instance Cache Poisoning_CVE-2026-44552

{
    "lastseen": "",
    "description": "Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the tool_servers and terminal_servers keys in utils/tools.py do use a prefix. When two or more Open WebUI instances share a Redis database (a supported and documented deployment pattern, e.g., for multi-region deployments, blue-green setups, or cluster topologies), the unprefixed keys collide. An admin on Instance A writing to tool_servers overwrites the value read by Instance B \u2014 causing Instance B's users to receive Instance A's tool server configuration. This vulnerability is fixed in 0.9.0.",
    "published": "2026-05-15T19:57:22.801Z",
    "modified": "2026-05-15T19:57:22.801Z",
    "type": "cve",
    "title": "Open WebUI: Redis Cache Keys tool_servers and terminal_servers Missing Instance Prefix Enable Cross-Instance Cache Poisoning",
    "source": "GitHub_M",
    "references": "https://github.com/open-webui/open-webui/security/advisories/GHSA-3x8w-4f7p-xxc2",
    "id": "CVE-2026-44552",
    "bulletinFamily": "",
    "cwe": [
        "CWE-668"
    ],
    "cvelist": null,
    "sourceData": "open-webui open-webui < 0.9.0",
    "sourceHref": "",
    "cvss": {
        "score": 8.7,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "open-webui",
    "version": "< 0.9.0",
    "vendor": "open-webui",
    "ai_description": "Redis Cache Keys tool_servers and terminal_servers Missing Instance Prefix Enable Cross-Instance Cache Poisoning",
    "ai_severity": "High",
    "ai_vendor": "Open WebUI",
    "ai_product": "Open WebUI",
    "ai_version": "< 0.9.0",
    "ai_score": 8.7
}