A flaw was found in RESTEasy client in all versions of RESTEasy up to 4.5.6.Final. It may allow client users to obtain the server's potentially sensitive information in headers, cookies and body when the server got WebApplicationException from the RESTEasy client call.

A cross-site scripting (XSS) flaw was found in RESTEasy in versions before 3.11.1.Final and before 4.5.3.Final, where it did not properly handle URL encoding when the RESTEASY003870 exception occurs. An attacker could use this flaw to launch a reflected XSS attack.