The pcs packages provide a command-line configuration system for the Pacemaker and Corosync utilities.
A command injection flaw was found in the pcsd web UI. An attacker able to trick a victim that was logged in to the pcsd web UI into visiting a specially crafted URL could use this flaw to execute arbitrary code with root privileges on the server hosting the web UI. (CVE-2015-5190)
A race condition was found in the way the pcsd web UI backend performed authorization of user requests. An attacker could use this flaw to send a request that would be evaluated as originating from a different user, potentially allowing the attacker to perform actions with permissions of a more privileged user. (CVE-2015-5189)
These issues were discovered by Tomáš Jelínek of Red Hat.
All pcs users are advised to upgrade to these updated packages, which contain backported patches to correct these issues.