Executive brief
n8n is an automation platform used to connect different business applications and automate workflows. A security flaw in the 'Merge' tool allows a user with basic workflow creation permissions to interfere with the system's shared memory. This could allow an attacker to secretly intercept or view sensitive data being processed by other users' workflows on the same system.
Technical details
A prototype pollution vulnerability exists in the n8n Merge node when used in SQL Query mode. The root cause is the caching and reuse of the sandbox context across different workflow executions on the same instance. An authenticated attacker with workflow creation privileges can introduce prototype mutations that persist in the shared environment. This allows the attacker to intercept or manipulate data processed by subsequent Merge SQL executions belonging to other users or projects. The issue is fixed in versions 2.25.7 and 2.26.2; workarounds include disabling the Merge node via environment variables.
Affected products
- n8n-io n8n < 2.25.7, >= 2.26.0 < 2.26.2
Timeline
- 2026-06-10: advisory: GitHub advisory published by vendor
- 2026-06-23: disclosed: CVE published to NVD