n8n: Prototype Pollution via Dot-Notation Field Names Leads To Instance-Wide Denial of Service

Summary

## Impact The Edit Fields (Set) node assigned output fields through a dot-notation path setter without restricting the field name, so an authenticated user could name a field after an inherited built-in method path and corrupt a shared global in the main Node.js process. Because that global was used on the request-authentication path, the instance then failed every authenticated request, causing a instance-wide denial of service for all users until the process was restarted. ## Patches The issue has been fixed in n8n versions 1.123.67, 2.31.5, and 2.32.1. Users should upgrade to one of these versions or later to remediate the vulnerability. ## Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Restrict n8n instance access to fully trusted users only. - Disable or restrict workflow creation and execution permissions for untrusted users. - Monitor for unexpected process-wide HTTP 500 errors and restart the process promptly if they occur. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.