The vulnerability in n8n arises because credential-access validation only checks top-level credentials of a node but fails to validate credentials referenced inside an Execute Sub-workflow node's inline workflow JSON. An attacker with editor access to a shared workflow can embed a credential they are not authorized to use inside the inline JSON of a sub-workflow. This bypasses both save-time and runtime validation, allowing the attacker to use or exfiltrate the credential in the context of the parent workflow's project. Exploitation requires that workflow sharing is enabled, the attacker has editor access to the shared workflow, and the attacker knows the credential's ID. The vulnerability is addressed by patches in n8n versions 1.123.67, 2.31.5, and 2.32.1.

An attacker with editor access to a shared workflow can access or exfiltrate credentials they are not authorized to use by embedding them in inline sub-workflow JSON. This compromises credential confidentiality and potentially allows unauthorized actions within the affected n8n instance. The vulnerability requires specific conditions: enabled workflow sharing, editor access, and knowledge of credential IDs. There are no known exploits in the wild at this time.

A fix is available 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. If immediate upgrade is not possible, administrators should restrict workflow sharing to trusted users, avoid granting editor access to untrusted members on workflows using sensitive credentials, audit shared workflows for Execute Sub-workflow nodes with inline JSON referencing credentials, and restrict network egress from the n8n instance to prevent data exfiltration. These workarounds do not fully mitigate the risk and should be considered temporary.