Executive brief
n8n is a workflow automation platform that allows users to create, share, and execute automated business processes. The vulnerability permits workflow editors and API users to plant malicious nodes that reference credentials they do not own; when another user with access to those credentials executes the workflow, the credentials are exposed to attacker-controlled endpoints, enabling credential theft and account compromise.
Technical details
The vulnerability is an authorization bypass in n8n's credential validation logic (CWE-863). When processing inline workflow JSON in nodes that execute sub-workflows (such as the Workflow Tool node), n8n fails to validate whether the acting user owns the credentials being referenced. An attacker with editor access to a shared workflow, or any user able to create/update workflows via REST API, Public API, or MCP, can persist nodes with credential references they do not own. When the workflow executes under an identity that holds the credential, the inline sub-workflow resolves the credential secret and can transmit it to an attacker-controlled endpoint. The attack requires: (1) low-privilege access to create/edit workflows, and (2) a subsequent execution by a user holding the targeted credential. Patches are available in versions 2.35.4 and 2.36.2.
Affected products
- n8n n8n before 2.35.4 and 2.36.x before 2.36.2
Timeline
- 2026-08-19: disclosed: GitHub Security Advisory GHSA-4r56-g65c-fm83 published
- 2026-09-03: advisory: CVE-2026-85166 published on NVD
- 2026-09-03: patched: Patches available in n8n 2.35.4 and 2.36.2