# CVE-2026-54309: n8n missing authentication in MCP Browser HTTP transport

Source: https://junglewise.ai/threats/cve-2026-54309-n8n-missing-authentication-in-mcp-browser-http-transport  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-23. Updated: 2026-06-23  
License: CC BY 4.0 with a link back

CVE-2026-54309 · Severity: critical · CVSS 10 · Published 2026-06-23

n8n is an automation platform used to connect different software services and automate business workflows. A security flaw in its browser-control component allows unauthorized individuals to remotely take control of a user's web browser if the system is configured in a specific way. An attacker could use this to navigate to websites, run malicious scripts, or steal sensitive information like login cookies and saved data from the user's browser profile.

Technologies: [N8n](https://junglewise.ai/threats/technologies/n8n), [n8n (npm)](https://junglewise.ai/threats/technologies/npm-n8n). Vendors: [N8n](https://junglewise.ai/threats/vendors/n8n), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-54309 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-54309 being exploited in the wild.

**How severe is CVE-2026-54309?** Critical severity, with a CVSS score of 10, published 23 June 2026.

**Which products and versions are affected?** N8n < 2.25.7, >= 2.26.0 < 2.26.2; n8n (npm) SEMVER:introduced=2.26.0,fixed=2.26.2.

**Is there a fix for CVE-2026-54309?** Yes. n8n (npm): upgrade to 2.26.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-54309 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-54309?** Check whether you run N8n or n8n (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- n8n (npm): upgrade to 2.26.2 or later

  ```sh
  npm install n8n@2.26.2
  ```


## Technical details

A missing authentication vulnerability (CWE-306) exists in the @n8n/mcp-browser component of n8n when configured to use HTTP transport (--transport http). The Model Context Protocol (MCP) endpoint fails to validate requests, allowing any network-reachable attacker to initialize sessions and invoke browser-control tools. If the n8n AI Browser Bridge extension is active, an attacker can perform JavaScript evaluation, navigate the browser, and access cookies or local storage within the user's active browser profile. The default 'stdio' transport is not affected. Patches are available in versions 2.25.7 and 2.26.2.

## Affected products

- n8n-io n8n < 2.25.7, >= 2.26.0 < 2.26.2

## Identifiers

- CVE-2026-54309
- GHSA-qrx8-25qr-5r7v

## Timeline

- 2026-06-10: advisory: GitHub advisory published by vendor
- 2026-06-23: disclosed: NVD publication date

## References

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

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