n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, an authenticated user with a valid API key scoped to variable:list could read variables from projects they are not a member of by supplying an arbitrary projectId query parameter to the public API variables endpoint. The handler queried the variables repository directly without enforcing project membership checks, bypassing the authorization-aware service layer used by the internal enterprise controller.

If variables were misused to store sensitive information such as credentials or tokens, they should be rotated immediately. This issue only affects licensed enterprise or team deployments with multiple projects and the variables feature enabled. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.