This indicates an attempt to exploit one of several related vulnerabilities in X.Org Font Server.
X.Org Font Server contains multiple vulnerabilities that may be triggered when handling incoming "QueryXExtents8", "QueryXExtents16", "QueryXBitmaps8" or "QueryXBitmaps1" protocol requests.
X.Org Foundation - X Font Server (1.0.4 (X11R7.3) and prior.
System Compromise: Remote attackers can gain control of vulnerable systems.
Upgrade to X.Org XFS 1.0.5.