n8n: Prototype Pollution enables confused-deputy execution via public webhooks

Medium5.4CVE-2026-54306 · Published Jun 16, 2026 · updated Jul 20, 2026

## Impact A prototype pollution vulnerability allowed a crafted public webhook payload to inject attacker-controlled fields into workflow data during internal object copying. These fields could be surfaced and consumed as normal values by downstream built-in nodes. Where a workflow combines a public webhook with action nodes that consume the resulting fields, an attacker could cause the workflow to act as a confused deputy , targeting unintended records or issuing outbound requests using the workflow owner's configured credentials. ## Patches The issue has been fixed in n8n versions 2.25.7, and 2.26.2. 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: - Avoid exposing public (unauthenticated) webhook workflows that pass incoming data through transform nodes into action nodes with sensitive credentials or database operations. - Limit workflow creation and editing permissions to fully trusted users only. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.