It was reported that pcs package is vulnerable to command injection with root privileges. A user supplied string is used to in running a system command. If the user uses escape characters they can run a command as the root user on the system. To do this the user must already have access to login to pcsd (Be a member of the hacluster group).
Acknowledgement: This issue was discovered by Tomáš Jelínek of Red Hat.
This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Via RHSA-2015:1700 https://rhn.redhat.com/errata/RHSA-2015-1700.html