Multiple integer overflows in X.Org X Window System (aka X11 or X) X11R1 and X.Org Server (aka xserver and xorg-server) before 1.16.3 allow remote authenticated users to cause a denial of service (crash) or possibly execute arbitrary code via a crafted request to the (1) ProcPutImage, (2) GetHosts, (3) RegionSizeof, or (4) REQUEST_FIXED_SIZE function, which triggers an out-of-bounds read or write.