It was discovered that Undertow before 1.4.17, 1.3.31 and 2.0.0 processes http request headers with unusual whitespaces which can cause possible http request smuggling.
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
access.redhat.com/errata/RHSA-2018:0002
access.redhat.com/errata/RHSA-2018:0003
access.redhat.com/errata/RHSA-2018:0004
access.redhat.com/errata/RHSA-2018:0005
access.redhat.com/errata/RHSA-2018:1322
bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-12165