Alex Joseph
Understanding the n8n OAuth Vulnerability
A significant security vulnerability has been discovered in n8n, a popular open-source workflow automation platform. This flaw, tracked as CVE-2026-65594, could allow regular users with member-level access to potentially take control of and execute other users’ automated workflows. If exploited, this could lead to unauthorized access to sensitive data and disruption of user and project isolation within the n8n environment.
CVE Details
- Product: n8n
- Published: July 22, 2026
- Severity: Medium
- Status: Analyzed
Affected Products
This vulnerability impacts n8n instances running versions from 2.27.0 up to, but not including, 2.29.8, and versions from 2.30.0 up to, but not including, 2.30.1. Both the Community and Enterprise editions of n8n, specifically those running on Node.js, are affected. The critical condition for this vulnerability is the presence of at least one active workflow utilizing an MCP Server Trigger node configured with n8n OAuth2 authentication.
Current Status
The vulnerability, identified by CVE-2026-65594, has been thoroughly analyzed by security researchers and the n8n team.
Severity Level
This issue is classified as “Medium” severity, with a CVSS v4 base score of 6.5. This score indicates that while exploiting the vulnerability requires specific conditions, a successful attack carries notable risks. An attacker with low privileges could exploit this flaw over a network without requiring any user interaction. The primary concern is a high impact on the confidentiality of data in subsequent systems and a low impact on the integrity of the vulnerable system.
Possible Solutions
To protect your n8n instance from this vulnerability, it is crucial to update to a patched version as soon as possible:
- Upgrade to n8n version 2.29.8 or any later version.
- Upgrade to n8n version 2.30.1 or any later version.
If an immediate upgrade is not feasible, the following temporary mitigation steps can help reduce the risk, though they do not fully eliminate it:
- Restrict User Access: Limit access to your n8n instance strictly to fully trusted users only.
- Audit Workflows: Carefully review any active workflows that use the MCP Server Trigger configured with n8n OAuth2 authentication. Consider switching to a different authentication method or temporarily deactivating these workflows until you can apply the necessary patches.
These workarounds are temporary measures. The recommended long-term solution is to apply the official security updates.
For more insights into securing your automation processes, you might find our article on Best Practices for Secure Workflow Automation helpful.
References
https://github.com/n8n-io/n8n/security/advisories/GHSA-q5xf-xhwf-cwqf
https://www.vulncheck.com/advisories/n8n-before-missing-oauth-authorization-check
