The pivot_root implementation in fs/namespace.c in the Linux kernel through 3.17 does not properly interact with certain locations of a chroot directory, which allows local users to cause a denial of service (mount-tree loop) via . (dot) values in both arguments to the pivot_root system call.
https://exchange.xforce.ibmcloud.com/vulnerabilities/96921
https://bugzilla.redhat.com/show_bug.cgi?id=1151095
https://access.redhat.com/errata/RHSA-2017:2077
https://access.redhat.com/errata/RHSA-2017:1842
http://www.ubuntu.com/usn/USN-2514-1
http://www.ubuntu.com/usn/USN-2513-1
http://www.ubuntu.com/usn/USN-2420-1
http://www.ubuntu.com/usn/USN-2419-1
http://www.securitytracker.com/id/1030991
http://www.securityfocus.com/bid/70319
http://www.openwall.com/lists/oss-security/2014/10/08/21
http://lists.opensuse.org/opensuse-security-announce/2015-04/msg00015.html