n8n versions before 1.123.64, 2.29.8, and 2.30.1 contain a privilege escalation vulnerability in Enterprise SSO instance-role provisioning. The provisioning path maps an IdP-asserted role claim to an n8n global role but does not prevent assignment of the global:owner role (unlike the token-exchange identity path, which rejects it). An SSO-authenticated user whose instance-role claim resolves to global:owner is provisioned as instance owner, gaining full administrative control over workflows, credentials, users, and instance configuration. Exploitation requires that Enterprise SSO is configured, instance-role provisioning is enabled via N8N_SSO_SCOPES_PROVISION_INSTANCE_ROLE (disabled by default), and the attacker controls the instance-role claim value issued by the IdP.