The DBE extension in X.Org X Window System (aka X11 or X) X11R6.1 and X.Org Server (aka xserver and xorg-server) before 1.16.3 allows remote authenticated users to cause a denial of service (out-of-bounds read or write) or possibly execute arbitrary code via a crafted length or index value to the (1) ProcDbeSwapBuffers or (2) SProcDbeSwapBuffers function.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.