Xen 3.3.x through 4.5.x does not properly restrict access to PCI MSI mask bits, which allows local x86 HVM guest users to cause a denial of service (unexpected interrupt and host crash) via unspecified vectors.
Xen 3.3.x through 4.5.x does not properly restrict write access to the host MSI message data field, which allows local x86 HVM guest administrators to cause a denial of service (host interrupt handling confusion) via vectors related to qemu and accessing spanning multiple fields.
Xen 4.2.x through 4.5.x does not initialize certain fields, which allows certain remote service domains to obtain sensitive information from memory via a (1) XEN_DOMCTL_gettscinfo or (2) XEN_SYSCTL_getdomaininfolist request.
QEMU, as used in Xen 3.3.x through 4.5.x, does not properly restrict access to PCI command registers, which might allow local HVM guest users to cause a denial of service (non-maskable interrupt and host crash) by disabling the (1) memory or (2) I/O decoding for a PCI Express device and then accessing the device, which triggers an Unsupported Request (UR) response.
The XEN_DOMCTL_memory_mapping hypercall in Xen 3.2.x through 4.5.x, when using a PCI passthrough device, is not preemptible, which allows local x86 HVM domain users to cause a denial of service (host CPU consumption) via a crafted request to the device model (qemu-dm).
Xen 4.3.x, 4.4.x, and 4.5.x, when using toolstack disaggregation, allows remote domains with partial management control to cause a denial of service (host lock) via unspecified domctl operations.
Xen 4.5.x and earlier enables certain default backends when emulating a VGA device for an x86 HVM guest qemu even when the configuration disables them, which allows local guest users to obtain access to the VGA console by (1) setting the DISPLAY environment variable, when compiled with SDL support, or connecting to the VNC server on (2) ::1 or (3) 127.0.0.1, when not compiled with SDL support.
The x86 emulator in Xen 3.2.x through 4.5.x does not properly ignore segment overrides for instructions with register operands, which allows local guest users to obtain sensitive information, cause a denial of service (memory corruption), or possibly execute arbitrary code via unspecified vectors.
Xen 3.3.x through 4.5.x and the Linux kernel through 3.19.1 do not properly restrict access to PCI command registers, which might allow local guest OS users to cause a denial of service (non-maskable interrupt and host crash) by disabling the (1) memory or (2) I/O decoding for a PCI Express device and then accessing the device, which triggers an Unsupported Request (UR) response.
The HYPERVISOR_xen_version hypercall in Xen 3.2.x through 4.5.x does not properly initialize data structures, which allows local guest users to obtain sensitive information via unspecified vectors.