{"id":"CVE-2026-54309","aliases":["GHSA-qrx8-25qr-5r7v"],"url":"https://o3.security/vulnerability/CVE-2026-54309","summary":"n8n: n8n MCP Browser HTTP Transport Exposes Unauthenticated Browser-Control Sessions","details":"## Impact\nWhen `@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.\n\nWhere 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.\n\nThis issue only affects instances where `@n8n/mcp-browser` is run with the HTTP transport (`--transport http`). The default transport is stdio, which is not affected.\n\n## Patches\nThe issue has been fixed in n8n versions 2.25.7, and 2.26.2. Users should upgrade to one of these versions or later to remediate the vulnerability.\n\n## Workarounds\nIf upgrading is not immediately possible, administrators should consider the following temporary mitigations:\n- Avoid running `@n8n/mcp-browser` with the HTTP transport; use the default stdio transport instead.\n- If HTTP transport is required, restrict network access to the listening port to trusted clients only using host-based firewall rules.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.","published":"2026-06-23T15:36:13.270Z","modified":"2026-08-12T03:51:13.637449614Z","cvss":null,"epss":{"score":0.00546,"percentile":0.4383,"asOf":"2026-09-08"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"n8n","fixedVersion":"2.26.2"},{"ecosystem":"npm","name":"n8n","fixedVersion":"2.25.7"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54309.json"},{"type":"ADVISORY","url":"https://github.com/n8n-io/n8n/security/advisories/GHSA-qrx8-25qr-5r7v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54309"},{"type":"PACKAGE","url":"https://github.com/n8n-io/n8n"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:13.637449614Z"}}