GHSA-cw9w-vv67-hf73: n8n: Per-Resource OAuth Consent Bypass via Unbound Refresh Token Resource Substitution
Summary
n8n had an OAuth security flaw where refresh tokens (credentials that let apps get new access tokens without re-authorization) could be used on different resources than originally approved. An attacker could trick a user into approving their app for one workflow, then use the refresh token to access a different workflow without permission. The fix binds refresh tokens to their original resource and rejects mismatched requests.
Solution / Mitigation
The issue has been fixed in n8n versions 2.38.1 and 2.37.7. Users should upgrade to this version or later to remediate the vulnerability. If upgrading is not immediately possible, administrators should: restrict n8n instance access to fully trusted users only; deactivate MCP Trigger, form, and webhook workflows protected by n8n OAuth if not required; audit connected OAuth clients and revoke unrecognized or unneeded ones; and require re-authorization for all existing OAuth clients after upgrading, as previously issued refresh tokens did not store the original resource binding. The source notes these workarounds do not fully remediate the risk and should only be used as short-term measures.
Vulnerability Details
EPSS: 0.3%
Yes
September 10, 2026
Classification
Affected Vendors
Affected Packages
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Original source: https://github.com/advisories/GHSA-cw9w-vv67-hf73
First tracked: September 10, 2026 at 08:01 PM
Classified by LLM (prompt v3) · confidence: 75%