GHSA-35q8-9mj6-wjmf: n8n: SSO Instance-Role Provisioning Allows Privilege Escalation to Instance Owner

Impact 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. Patches The issue has been fixed in n8n versions 1.123.64, 2.29.8, and 2.30.1. 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: - Disable instance-role provisioning by unsetting or setting N8N_SSO_SCOPES_PROVISION_INSTANCE_ROLE=false. - Audit IdP claim mappings to ensure no user-controllable attribute can supply the instance-role claim value. - Restrict SSO access to fully trusted users only. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.