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CVE-2026-54309: n8n @n8n/mcp-browser: missing authentication on HTTP MCP endpoint

The @n8n/mcp-browser package of n8n, when run with the HTTP transport, exposes an MCP endpoint that accepts session initialization and tool calls without authentication, a weakness classified as CWE-306. Where the n8n AI Browser Bridge extension is installed and connected, an unauthenticated caller could reach browser-control functions on the user's real browser profile. The vendor fixes are in versions 2.25.7 and 2.26.2, and the record shows no CISA KEV listing.

Published Oct 13, 2026 · Updated Oct 13, 2026 · Ler em português

Overview

The @n8n/mcp-browser component of n8n can run in HTTP transport mode. According to the advisory summarized in the record, its MCP endpoint accepts session initialization and tool invocation requests without authentication. The issue is tracked as CVE-2026-54309 and is fixed in versions 2.25.7 and 2.26.2.

Impact

  • Any network-reachable client can open an MCP session, according to the record.
  • Any website the user visits may be able to reach the same endpoint, according to the record.
  • Where the n8n AI Browser Bridge extension is installed and connected, the record describes access to navigation, JavaScript evaluation, and cookie and storage access in the user's real browser profile.
  • NVD scores the issue 10.0 under CVSS 3.1 (critical). The GitHub CNA scores it 8.8 under CVSS 4.0.

Affected products and versions

The record lists the product as N8n N8n with these ranges: below 2.25.7, and 2.26.0 up to but not including 2.26.2. The issue only applies when @n8n/mcp-browser runs with the HTTP transport (--transport http).

Exploitation status

The record shows KEV listed as false. No confirmed exploitation appears in the sources consulted, and no EPSS score is provided.

Remediation and mitigation

  • Upgrade n8n to 2.25.7 or later on the 2.25 line, or to 2.26.2 or later on the 2.26 line, as stated in the vendor advisory.
  • If an upgrade cannot be done immediately, the vendor advisory lists mitigation guidance. Review it at the GitHub Security Advisory GHSA-qrx8-25qr-5r7v.
  • Stop running @n8n/mcp-browser in HTTP transport mode where it is not required.
  • Limit network access to any HTTP endpoint of this component to trusted hosts.
  • Remove or disable the browser bridge extension on systems where it is not needed.

Detection guidance

  • Inventory where @n8n/mcp-browser is installed and whether it runs with the HTTP transport.
  • Review network exposure of those services and identify any reachable from untrusted networks.
  • Review logs for unexpected MCP session initialization or tool activity from unknown sources.
  • Check whether the browser bridge extension is installed and connected on hosts running the affected component.

Limitations of the available information

The record gives no exploit details, no public proof-of-concept information, and no indication of real-world abuse. The record states affected ranges that differ slightly from the prose wording prior to 2.25.7 and 2.26.2; both are reported here as given. The advisory text itself was not reviewed beyond the record's references.

Frequently asked questions

Is this vulnerability known to be actively exploited?

The record shows KEV listed as false. No confirmed exploitation appears in the sources consulted.

Which versions are fixed?

The record states the issue is fixed in 2.25.7 and 2.26.2. The listed affected ranges are below 2.25.7 and from 2.26.0 up to but not including 2.26.2.

Does this affect every n8n installation?

No. According to the record, it only affects instances where @n8n/mcp-browser runs with the HTTP transport (--transport http).

This analysis was drafted with AI assistance from verified source data and automatically checked against it.