The RichFaces Framework 3.X through 3.3.4 is vulnerable to Expression Language (EL) injection via the UserResource resource. A remote, unauthenticated attacker could exploit this to execute arbitrary code using a chain of java serialized objects via org.ajax4jsf.resource.UserResource$UriData.
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-14667
https://access.redhat.com/errata/RHSA-2018:3581
https://access.redhat.com/errata/RHSA-2018:3519
https://access.redhat.com/errata/RHSA-2018:3518
https://access.redhat.com/errata/RHSA-2018:3517
http://www.securitytracker.com/id/1042037
http://seclists.org/fulldisclosure/2020/Mar/21
http://packetstormsecurity.com/files/156663/Richsploit-RichFaces-Exploitation-Toolkit.html