Jenkins before 1.502 and LTS before 1.480.3 allows remote authenticated users with write access to cause a denial of service via a crafted payload.
https://wiki.jenkins-ci.org/display/SECURITY/Jenkins+Security+Advisory+2013-02-16
https://bugzilla.redhat.com/show_bug.cgi?id=914879
http://www.securityfocus.com/bid/57994
http://www.openwall.com/lists/oss-security/2013/02/21/7
http://www.cloudbees.com/jenkins-advisory/jenkins-security-advisory-2013-02-16.cb