Missing Authentication for Critical Function Affecting @n8n/mcp-browser package, versions <0.8.1>=0.9.0 <0.9.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published1 Jul 2026
- disclosed23 Jun 2026
- creditESPanda666
Introduced: 23 Jun 2026
CVE-2026-54309 (opens in a new tab)How to fix?
Upgrade @n8n/mcp-browser to version 0.8.1, 0.9.1 or higher.
Overview
@n8n/mcp-browser is a Browser automation MCP tools built on Playwright, WebDriver BiDi, and safaridriver
Affected versions of this package are vulnerable to Missing Authentication for Critical Function through the MCP server’s HTTP request handling. An attacker can take over a user’s browser session by sending requests to the MCP endpoint and invoking browser tools without presenting any credentials. When the extension is installed and the browser connection is active, a network-reachable client or a website the user visits can reach the HTTP listener and use the real browser profile to navigate, run JavaScript, and read cookies and storage. This exposes browser state and allows the attacker to act using the user’s browser capabilities.
Notes
- The issue is limited to
@n8n/mcp-browserwhen it is started in HTTP transport mode; the default stdio transport is not part of the vulnerable path.
Workarounds
- Avoid running
@n8n/mcp-browserwith--transport http; use the defaultstdiotransport instead to prevent unauthenticated network or website access to browser-control sessions. - If you must use HTTP transport, restrict the listening port to trusted clients only with host-based firewall rules to block untrusted network access to the MCP endpoint.