n8n-io n8n up to 2.25.6/2.26.1 MCP Endpoint missing authentication

Summaryinfo

A vulnerability categorized as critical has been discovered in n8n-io n8n up to 2.25.6/2.26.1. This affects an unknown part of the component MCP Endpoint. Such manipulation leads to missing authentication. This vulnerability is listed as CVE-2026-54309. The attack may be performed from remote. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in n8n-io n8n up to 2.25.6/2.26.1. It has been rated as critical. Affected by this issue is an unknown functionality of the component MCP Endpoint. The manipulation with an unknown input leads to a missing authentication vulnerability. Using CWE to declare the problem leads to CWE-306. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-54309 since 06/12/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available.

Upgrading to version 2.25.7 or 2.26.2 eliminates this vulnerability.

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Productinfo

Vendor

• n8n-io

Name

• n8n

Version

• 2.25.0
• 2.25.1
• 2.25.2
• 2.25.3
• 2.25.4
• 2.25.5
• 2.25.6
• 2.26.0
• 2.26.1

Website

• Product: https://github.com/n8n-io/n8n/

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