Understanding the n8n-MCP Information Disclosure Risk
A security flaw has been identified in n8n-MCP, a server designed to provide AI assistants with access to n8n node documentation, properties, and operations. This vulnerability could lead to sensitive information being exposed in system logs.
Specifically, when n8n-MCP was configured to run in HTTP transport mode, it would record details from incoming requests to its POST /mcp endpoint into its server logs. This happened regardless of whether the requests were authenticated or not. While unauthorized requests were correctly blocked, the problem was that sensitive data like bearer tokens from authorization headers, per-tenant API keys in multi-tenant setups, and JSON-RPC request payloads could still end up in these logs.
For organizations that collect, forward, or allow external viewing of their logs (for example, in shared log storage or Security Information and Event Management (SIEM) systems), this unintended logging could result in the disclosure of critical information. It’s important to note that this flaw did not bypass access controls; unauthenticated requests were still denied as expected. The risk primarily lies in the persistence and potential access to sensitive data within the log files themselves.
CVE Details
- Product: n8n-MCP
- CVE ID: CVE-2026-41495
- Published Date: May 8, 2026
- Last Modified: May 14, 2026
- Status: Analyzed
Affected Products
The vulnerability affects all versions of n8n-MCP prior to version 2.47.11. If you are running an earlier version, your system may be at risk.
Current Status
The vulnerability status is “Analyzed,” meaning it has been reviewed and validated. A patch is available to address this issue.
Severity Level
This information disclosure vulnerability is rated as Medium Severity. While direct access to systems wasn’t granted through this flaw, the exposure of sensitive data in logs could have significant downstream impacts, potentially leading to further compromise if those logs are accessed by unauthorized parties.
Possible Solutions
The good news is that a fix is available! To protect your n8n-MCP instances from this vulnerability, you should update to the patched version as soon as possible.
- Upgrade to Version 2.47.11: The issue has been officially patched in n8n-MCP version 2.47.11. Users are strongly advised to upgrade their installations to this version or a later release to mitigate the risk.
For detailed installation and update instructions, please refer to the official n8n-MCP documentation.
References
https://github.com/czlonkowski/n8n-mcp/releases/tag/v2.47.11
https://github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-pfm2-2mhg-8wpx
