n8n: Credential exfiltration via Allowed HTTP Request Domains Bypass
Date: 2026-05
Affected: npm/n8n
Attack vector: data-exfiltration
Category: vulnerability-disclosure
Severity: Medium
CWE: CWE-918
CVSS: 9.1 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L)

## Impact The `POST /rest/dynamic-node-parameters/options` endpoint allowed any authenticated user to cause the n8n server to issue HTTP requests including credentials bypassing the intended restrictions on which hosts could be contacted for that credential (Allowed HTTP Request Domains). The user needed to be authenticated and have access to the credential. ## Patches The issue has been fixed in n8n version 2.20.0. Users should upgrade to this version or later to remediate the vulnerability. ## Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Restrict n8n access to fully trusted users only. - Limit credential sharing to users who genuinely require access to those credentials. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.


Mitigations:

Architectural layers (MAESTRO):