The TLS session cache in FreeRADIUS 2.1.1 through 2.1.7, 3.0.x before 3.0.14, 3.1.x before 2017-02-04, and 4.0.x before 2017-02-04 fails to reliably prevent resumption of an unauthenticated session, which allows remote attackers (such as malicious 802.1X supplicants) to bypass authentication via PEAP or TTLS.
https://security.gentoo.org/glsa/201706-27
https://access.redhat.com/errata/RHSA-2017:1581
http://www.securitytracker.com/id/1038576
http://www.securityfocus.com/bid/98734