From the Red Hat advisory:
* A vulnerability was discovered in spice in the server's protocol
handling. An authenticated attacker could send crafted messages to
the spice server causing a heap overflow leading to a crash or
possible code execution. (CVE-2016-9577)
* A vulnerability was discovered in spice in the server's protocol
handling. An attacker able to connect to the spice server could send
crafted messages which would cause the process to crash.
(CVE-2016-9578)
Graham Christensen