The XVideo extension in XFree86 4.0.0, X.Org X Window System (aka X11 or X) X11R6.7, 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) SProcXvQueryExtension, (2) SProcXvQueryAdaptors, (3) SProcXvQueryEncodings, (4) SProcXvGrabPort, (5) SProcXvUngrabPort, (6) SProcXvPutVideo, (7) SProcXvPutStill, (8) SProcXvGetVideo, (9) SProcXvGetStill, (10) SProcXvPutImage, (11) SProcXvShmPutImage, (12) SProcXvSelectVideoNotify, (13) SProcXvSelectPortNotify, (14) SProcXvStopVideo, (15) SProcXvSetPortAttribute, (16) SProcXvGetPortAttribute, (17) SProcXvQueryBestSize, (18) SProcXvQueryPortAttributes, (19) SProcXvQueryImageAttributes, or (20) SProcXvListImageFormats function.