n8n: n8n MCP Browser HTTP Transport Exposes Unauthenticated Browser-Control Sessions_CVE-2026-54309

{
    "lastseen": "",
    "description": "n8n is an open source workflow automation platform. Prior to 2.25.7 and 2.26.2, when @n8n/mcp-browser is run in HTTP transport mode, the MCP endpoint accepts session initialization and tool invocation requests without any authentication. Any network-reachable client, or any website visited by the user, can establish an MCP session and invoke browser-control tools. Where the n8n AI Browser Bridge extension is installed and a browser connection is active, an unauthenticated caller can access browser-control capabilities including navigation, JavaScript evaluation, and cookie and storage access against the user's real browser profile. This issue only affects instances where @n8n/mcp-browser is run with the HTTP transport (--transport http). This vulnerability is fixed in 2.25.7 and 2.26.2.",
    "published": "2026-06-23T15:36:13.270Z",
    "modified": "2026-06-23T15:36:13.270Z",
    "type": "cve",
    "title": "n8n: n8n MCP Browser HTTP Transport Exposes Unauthenticated Browser-Control Sessions",
    "source": "GitHub_M",
    "references": "https://github.com/n8n-io/n8n/security/advisories/GHSA-qrx8-25qr-5r7v",
    "id": "CVE-2026-54309",
    "bulletinFamily": "",
    "cwe": [
        "CWE-306"
    ],
    "cvelist": null,
    "sourceData": "n8n-io n8n >= 2.26.0, < 2.26.2\nn8n-io n8n < 2.25.7",
    "sourceHref": "",
    "cvss": {
        "score": 8.8,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "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": "n8n",
    "version": ">= 2.26.0, < 2.26.2",
    "vendor": "n8n-io",
    "ai_description": "Unauthenticated access to browser-control capabilities via MCP endpoint",
    "ai_severity": "High",
    "ai_vendor": "n8n-io",
    "ai_product": "n8n",
    "ai_version": "2.26.0 to 2.26.2, < 2.25.7",
    "ai_score": 8.8
}