CVE-2026-65016: n8n: SSO Instance-Role Provisioning Allows Privilege Escalation to Instance Owner

n8n’s Enterprise SSO instance-role provisioning maps a role claim asserted by the configured Identity Provider (IdP) to an n8n global role and applies it during authentication. The provisioning path did not prevent assignment of the global:owner role, unlike the token-exchange identity path, which explicitly rejects it. As a result, an SSO-authenticated user whose instance-role claim resolves to global:owner is provisioned as an instance owner, obtaining full administrative control over all workflows, credentials, users, and instance configuration.

This is a privilege-escalation issue that is exploitable only under specific conditions. It affects instances where Enterprise SSO is configured and instance-role provisioning is enabled via the N8N_SSO_SCOPES_PROVISION_INSTANCE_ROLE flag, which is disabled by default. Exploitation additionally requires the attacker to control the value of the instance-role claim issued by the IdP. As this claim is typically an administrator-managed attribute, exploitation generally requires control over the IdP or its claim-to-role mapping, or a permissive IdP configuration in which a lower-privileged user can influence the claim value. Deployments that do not use Enterprise SSO, or that have instance-role provisioning disabled, are not affected.