In the X.Org X server before 2017-06-19, a user authenticated to an X Session could crash or execute code in the context of the X Server by exploiting a stack overflow in the endianness conversion of X Events.
Uninitialized data in endianness conversion in the XEvent handling of the X.Org X Server before 2017-06-19 allowed authenticated malicious users to access potentially privileged data from the X server.
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.
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.
Integer overflow in the ProcDRI2GetBuffers function in the DRI2 extension in X.Org Server (aka xserver and xorg-server) 1.7.0 through 1.16.x before 1.16.3 allows remote authenticated users to cause a denial of service (crash) or possibly execute arbitrary code via a crafted request, which triggers an out-of-bounds read or write.