RESTEasy's default exception mapper returns an exception's localized message in the HTTP 500 response body when no application exception mapper handles an unhandled exception other than a WebApplicationException. A remote unauthenticated client who can trigger such an exception may receive information included in the message. Fabio Burzigotti reports reproducing the behavior with RESTEasy 7.0.2.Final. The complete affected and fixed version ranges remain to be confirmed.