Amazon Linux AMI Security Advisory: ALAS-2015-543
Advisory Release Date: 2015-06-16 11:41 Pacific
A flaw was found in the way seunshare, a utility for running executables under a different security context, used the capng_lock functionality of the libcap-ng library. The subsequent invocation of suid root binaries that relied on the fact that the setuid() system call, among others, also sets the saved set-user-ID when dropping the binaries' process privileges, could allow a local, unprivileged user to potentially escalate their privileges on the system.
Run yum update libcap-ng to update your system.