GHSA-cj9h-qx8g-pq2g: n8n: Shared-Workflow Editor Can Exfiltrate Credentials via Inline Sub-Workflow JSON

The Execute Sub-workflow node can take its workflow as inline JSON (Source = "Parameter"). n8n's credential checks looked at the credentials on a node itself, but not at those embedded in that inline definition (CWE-863). A member with Editor access to a shared workflow could put a credential they were not allowed to use inside the inline JSON. It passed validation when the workflow was saved and again at runtime. It then resolved in the parent workflow's project context, so the credential worked.

The attacker needs workflow sharing to be enabled and explicit Editor access on a shared workflow. They also need the target credential's ID. With those, they can run requests with someone else's credential, or send it to an endpoint they control. The CVSS 4.0 vector lists high confidentiality impact on the instance and on connected systems, because stolen credentials unlock external services.

The risk is greatest in shared n8n projects where Editors are less trusted than credential owners.

Affected: n8n below 1.123.67 on the 1.x line, 2.0.0-rc.0 up to but not including 2.31.5, and 2.32.0. Only instances with workflow sharing enabled where untrusted users hold Editor access on shared workflows are practically exposed.

Check the version:

npm ls n8n

Then look for Execute Sub-workflow nodes with Source set to Parameter in shared workflows.

Upgrade to n8n 1.123.67, 2.31.5 or 2.32.1, or later. For an npm install, run npm install [email protected].

Temporary mitigations from the advisory, none of which fully remove the risk:

• Limit workflow sharing to fully trusted users. Do not give Editor access to untrusted members on workflows that use sensitive credentials.
• Audit shared workflows for Execute Sub-workflow nodes with Source = "Parameter" and review the inline definitions for unexpected credential references.
• Restrict network egress from the n8n instance to block attacker-controlled endpoints.

Open shared workflows that contain Execute Sub-workflow nodes with Source = "Parameter". Read the inline JSON for credential references, and compare each credential ID with the credentials the workflow's author may use. Flag any ID that belongs to another project. Check outbound traffic from the n8n host for connections to unfamiliar endpoints, and check the target services' logs for use of those credentials from n8n at odd times.

Impact

n8n's credential-access checks validated only a node's top-level credentials, not credentials referenced inside an Execute Sub-workflow node's inline workflow JSON. A member with editor access to a shared workflow could reference a credential they were not permitted to use inside that inline JSON; it passed both save-time and runtime validation and resolved in the parent workflow's project context, letting the member use or exfiltrate a credential they could not otherwise access.

Exploitation requires workflow sharing to be enabled and the attacker to have been explicitly granted Editor access to a shared workflow. The attacker must also know the target credential's ID.

Patches

The issue has been fixed 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.

Workarounds

If upgrading is not immediately possible, administrators should consider the following temporary mitigations:

• Restrict workflow sharing to fully trusted users only, and avoid granting Editor access to untrusted members on workflows that use sensitive credentials.
• Audit shared workflows for Execute Sub-workflow nodes with Source = "Parameter" and review their inline workflow definitions for unexpected credential references.
• Restrict network egress from the n8n instance to prevent connections to attacker-controlled endpoints.

These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.