Understanding the Critical Threat in n8n’s Browser Control
A serious security flaw, identified as CVE-2026-54309, has been discovered in n8n, an open-source workflow automation platform. This vulnerability, rated as CRITICAL, could allow unauthorized individuals to take control of a user’s browser activities under specific configurations. It affects the `@n8n/mcp-browser` component when operating in HTTP transport mode.
In simple terms, if your n8n setup uses the HTTP transport option for `@n8n/mcp-browser`, an attacker or even a malicious website you visit could potentially connect to your n8n instance without needing any login information. Once connected, they could then use your browser to navigate to websites, run their own scripts, and even access sensitive data like your browser cookies and stored information.
CVE Details
Product: n8n
Published Date: June 23, 2026
Severity: CRITICAL
Status: Analyzed
Affected Products
This vulnerability specifically impacts n8n instances where the `@n8n/mcp-browser` component is configured to run with the HTTP transport mode (`–transport http`). The default stdio transport mode is not affected.
Affected versions include all versions prior to:
- n8n 2.25.7
- n8n 2.26.2
Current Status
The vulnerability has been officially analyzed. The details, including its critical severity and potential impact, have been made public to ensure users are aware and can take necessary protective measures. Fixes are available and highly recommended.
Severity Level
CVE-2026-54309 carries a **CRITICAL** severity rating with a CVSS score of 10.0. This high score reflects the significant risk posed by the vulnerability, as it allows for complete unauthenticated control over a user’s browser profile, including access to sensitive data and the ability to execute arbitrary code within the browser context. The attack requires no special privileges or user interaction once the vulnerable configuration is in place and the n8n AI Browser Bridge extension is active.
Possible Solutions
Users of n8n are strongly urged to address this vulnerability immediately. The good news is that patches are available:
- Upgrade to n8n version 2.25.7 or later.
- Upgrade to n8n version 2.26.2 or later.
If an immediate upgrade is not feasible, temporary mitigation steps can be taken:
- Avoid HTTP Transport Mode: If possible, change the transport mode for `@n8n/mcp-browser` from HTTP to the default stdio transport. This is the most effective workaround.
- Restrict Network Access: If using HTTP transport is unavoidable, implement strict host-based firewall rules to limit network access to the listening port of `@n8n/mcp-browser` to only trusted clients.
These workarounds should be considered short-term solutions only, and a full upgrade to a patched version remains the best course of action to secure your n8n instance.
References
https://github.com/n8n-io/n8n/security/advisories/GHSA-qrx8-25qr-5r7v
