Executive brief
n8n is a workflow automation platform that allows users to create and run automated tasks combining multiple services and APIs. A prototype pollution vulnerability in public (unauthenticated) webhooks allows an attacker to inject malicious data that can be misused by downstream workflow actions, potentially causing the workflow to modify unintended records or make unauthorized requests using the workflow owner's credentials.
Technical details
A prototype pollution vulnerability exists in n8n's handling of public webhook payloads during internal object copying. An attacker can craft a malicious webhook payload that injects attacker-controlled fields into the workflow's internal data structures. These injected fields are then treated as legitimate values by downstream built-in action nodes (e.g., database operations, HTTP requests). This enables a confused deputy attack where the workflow, running with the owner's configured credentials, performs unintended actions such as modifying specific database records or issuing outbound requests to attacker-controlled destinations. The vulnerability requires the workflow to combine a public webhook endpoint with action nodes that consume the resulting data. The issue affects n8n versions prior to 2.25.7 and 2.26.0–2.26.1, and patches are available in versions 2.25.7 and 2.26.2 or later.
Affected products
- n8n n8n < 2.25.7, 2.26.0 to < 2.26.2
Timeline
- 2026-06-16: disclosed: Published on GitHub and OSV
- 2026-06-16: patched: Fixed in n8n 2.25.7 and 2.26.2
- 2026-06-23: other: NVD published CVE-2026-54306