It was found in Undertow before 1.3.28 that with non-clean TCP close, the Websocket server gets into infinite loop on every IO thread, effectively causing DoS.
rhn.redhat.com/errata/RHSA-2017-1409.html
www.securityfocus.com/bid/98965
access.redhat.com/errata/RHSA-2017:1410
access.redhat.com/errata/RHSA-2017:1411
access.redhat.com/errata/RHSA-2017:1412
access.redhat.com/errata/RHSA-2017:3454
access.redhat.com/errata/RHSA-2017:3455
access.redhat.com/errata/RHSA-2017:3456
access.redhat.com/errata/RHSA-2017:3458
bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2670
www.debian.org/security/2017/dsa-3906