EdgeX Foundry is an open source project for building a common open framework for internet-of-things edge computing. A vulnerability exists in the Edinburgh, Fuji, Geneva, and Hanoi versions of the software. When the EdgeX API gateway is configured for OAuth2 authentication and a proxy user is created, the client_id and client_secret required to obtain an OAuth2 authentication token are set to the username of the proxy user. A remote network attacker can then perform a dictionary-based password attack on the OAuth2 token endpoint of the API gateway to obtain an OAuth2 authentication token and use that token to make authenticated calls to EdgeX microservices from an untrusted network. OAuth2 is the default authentication method in EdgeX Edinburgh release. The default authentication method was changed to JWT in Fuji and later releases. Users should upgrade to the EdgeX Ireland release to obtain the fix. The OAuth2 authentication method is disabled in Ireland release. If unable to upgrade and OAuth2 authentication is required, users should create OAuth2 users directly using the Kong admin API and forgo the use of the `security-proxy-setup` tool to create OAuth2 users.