CVE-2026-54309

n8n: n8n MCP Browser HTTP Transport Exposes Unauthenticated Browser-Control Sessions

State: Published
Severity: 8.8 High
Published: Jun 23, 2026
Updated: Jun 23, 2026
Reserved: Jun 12, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	8.8 High	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	GitHub_M

Weaknesses

CWE-306 Missing Authentication for Critical Function

Affected Products

Product	Versions
n8nn8n-io	>= 2.26.0, < 2.26.2Affected < 2.25.7Affected

References

https://github.com/n8n-io/n8n/security/advisories/GHSA-qrx8-25qr-5r7v

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