The XGetImage function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving image type and geometry, which triggers out-of-bounds read operations.
The (1) XvQueryAdaptors and (2) XvQueryEncodings functions in X.org libXv before 1.0.11 allow remote X servers to trigger out-of-bounds memory access operations via vectors involving length specifications in received data.
The ProcPutImage function in dix/dispatch.c in X.Org Server (aka xserver and xorg-server) before 1.16.4 allows attackers to cause a denial of service (divide-by-zero and crash) via a zero-height PutImage request.
The authentication setup in XWayland 1.16.x and 1.17.x before 1.17.2 starts the server in non-authenticating mode, which allows local users to read from or send information to arbitrary X11 clients via vectors involving a UNIX socket.
Multiple off-by-one errors in the (1) MakeBigReq and (2) SetReqLen macros in include/X11/Xlibint.h in X11R6.x and libX11 before 1.6.0 allow remote attackers to have unspecified impact via a crafted request, which triggers a buffer overflow.
X.Org Server (aka xserver and xorg-server) before 1.16.3 and 1.17.x before 1.17.1 allows remote attackers to obtain sensitive information from process memory or cause a denial of service (crash) via a crafted string length value in a XkbSetGeometry request.
X.Org Server (aka xserver and xorg-server) 1.15.0 through 1.16.x 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) sproc_dri3_query_version, (2) sproc_dri3_open, (3) sproc_dri3_pixmap_from_buffer, (4) sproc_dri3_buffer_from_pixmap, (5) sproc_dri3_fence_from_fd, (6) sproc_dri3_fd_from_fence, (7) proc_present_query_capabilities, (8) sproc_present_query_version, (9) sproc_present_pixmap, (10) sproc_present_notify_msc, (11) sproc_present_select_input, or (12) sproc_present_query_capabilities function in the (a) DRI3 or (b) Present extension.
The SProcXFixesSelectSelectionInput function in the XFixes extension in X.Org X Window System (aka X11 or X) X11R6.8.0 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 value.
The Render extension in XFree86 4.0.1, 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) ProcRenderQueryVersion, (2) SProcRenderQueryVersion, (3) SProcRenderQueryPictFormats, (4) SProcRenderQueryPictIndexValues, (5) SProcRenderCreatePicture, (6) SProcRenderChangePicture, (7) SProcRenderSetPictureClipRectangles, (8) SProcRenderFreePicture, (9) SProcRenderComposite, (10) SProcRenderScale, (11) SProcRenderCreateGlyphSet, (12) SProcRenderReferenceGlyphSet, (13) SProcRenderFreeGlyphSet, (14) SProcRenderFreeGlyphs, or (15) SProcRenderCompositeGlyphs function.
The RandR extension in XFree86 4.2.0, 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) SProcRRQueryVersion, (2) SProcRRGetScreenInfo, (3) SProcRRSelectInput, or (4) SProcRRConfigureOutputProperty function.