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.

Multiple integer overflows in libXpm before 3.5.12, when a program requests parsing XPM extensions on a 64-bit platform, allow remote attackers to cause a denial of service (out-of-bounds write) or execute arbitrary code via (1) the number of extensions or (2) their concatenated length in a crafted XPM file, which triggers a heap-based buffer overflow.

Buffer underflow in X.org libXvMC before 1.0.10 allows remote X servers to have unspecified impact via an empty string.

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.

Multiple buffer overflows in the (1) XvQueryAdaptors and (2) XvQueryEncodings functions in X.org libXrender before 0.9.10 allow remote X servers to trigger out-of-bounds write operations via vectors involving length fields.

X.org libXrandr before 1.5.1 allows remote X servers to trigger out-of-bounds write operations by leveraging mishandling of reply data.

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.

Multiple integer overflows in X.org libXi before 1.7.7 allow remote X servers to cause a denial of service (out-of-bounds memory access or infinite loop) via vectors involving length fields.

X.org libXtst before 1.2.3 allows remote X servers to cause a denial of service (infinite loop) via a reply in the (1) XRecordStartOfData, (2) XRecordEndOfData, or (3) XRecordClientDied category without a client sequence and with attached data.

X.org libXi before 1.7.7 allows remote X servers to cause a denial of service (infinite loop) via vectors involving length fields.