jenkins is vulnerable to timing attack. A remote attacker is able to bypass CSRF protection mechanism through a brute-force approach of analyzing server response time to guess the value of CSRF tokens. This is due to the verification of the CSRF tokens not being performed using a constant-time algorithm.
rhn.redhat.com/errata/RHSA-2016-1773.html
access.redhat.com/errata/RHSA-2016:0711
access.redhat.com/security/updates/classification/#important
bugzilla.redhat.com/show_bug.cgi?id=1324664
jenkins.io/changelog-stable/#v1.642.2
rhn.redhat.com/errata/RHSA-2016-0711.html
wiki.jenkins-ci.org/display/SECURITY/Jenkins+Security+Advisory+2016-02-24