Xen 4.0.x through 4.7.x mishandle x86 task switches to VM86 mode, which allows local 32-bit x86 HVM guest OS users to gain privileges or cause a denial of service (guest OS crash) by leveraging a guest operating system that uses hardware task switching and allows a new task to start in VM86 mode.

Xen 4.1.x and 4.2.x, when the XSA-45 patch is in place, does not properly maintain references on pages stored for deferred cleanup, which allows local PV guest kernels to cause a denial of service (premature page free and hypervisor crash) or possibly gain privileges via unspecified vectors.

The HVMOPsetmemtype control in Xen 4.1 through 4.4.x allows local guest HVM administrators to cause a denial of service (hypervisor crash) or possibly execute arbitrary code by leveraging a separate qemu-dm vulnerability to trigger invalid page table translations for unspecified memory page types.

The physdevgetfreepirq hypercall in arch/x86/physdev.c in Xen 4.1.x and Citrix XenServer 6.0.2 and earlier uses the return value of the getfreepirq function as an array index without checking that the return value indicates an error, which allows guest OS users to cause a denial of service (invalid memory write and host crash) and possibly gain privileges via unspecified vectors.

Xen 3.3 through 4.1, when XSM is enabled, allows local users to cause a denial of service via vectors related to a "large memory allocation," a different vulnerability than CVE-2014-1891, CVE-2014-1893, and CVE-2014-1894.

Multiple integer overflows in the (1) FLASKGETBOOL and (2) FLASKSETBOOL suboperations in the flask hypercall in Xen 4.1.x, 3.3.x, 3.2.x, and earlier, when XSM is enabled, allow local users to cause a denial of service (processor fault) via unspecified vectors, a different vulnerability than CVE-2014-1891, CVE-2014-1892, and CVE-2014-1894.

Multiple integer overflows in the (1) FLASKGETBOOL, (2) FLASKSETBOOL, (3) FLASKUSER, and (4) FLASKCONTEXTTOSID suboperations in the flask hypercall in Xen 4.3.x, 4.2.x, 4.1.x, 3.2.x, and earlier, when XSM is enabled, allow local users to cause a denial of service (processor fault) via unspecified vectors, a different vulnerability than CVE-2014-1892, CVE-2014-1893, and CVE-2014-1894.

The HVMOPsetmemaccess HVM control operations in Xen 4.1.x for 32-bit and 4.1.x through 4.4.x for 64-bit allow local guest administrators to cause a denial of service (CPU consumption) by leveraging access to certain service domains for HVM guests and a large input.

Use-after-free vulnerability in the xccpupoolgetinfo function in Xen 4.1.x through 4.3.x, when using a multithreaded toolstack, does not properly handle a failure by the xccpumapalloc function, which allows local users with access to management functions to cause a denial of service (heap corruption) and possibly gain privileges via unspecified vectors.

CMPXCHG8B emulation in Xen 3.3.x through 4.7.x on x86 systems allows local HVM guest OS users to obtain sensitive information from host stack memory via a "supposedly-ignored" operand size prefix.

The PyGrub boot loader in Xen unstable before changeset 25589:60f09d1ab1fe, 4.2.x, and 4.1.x allows local para-virtualized guest users to cause a denial of service (memory consumption) via a large (1) bzip2 or (2) lzma compressed kernel image.

Xen 3.2.x through 4.4.x does not properly clean memory pages recovered from guests, which allows local guest OS users to obtain sensitive information via unspecified vectors.

The handlemmio function in arch/x86/hvm/io.c in the MMIO operations emulator for Xen 3.3 and 4.x, when running an HVM guest, does not properly reset certain state information between emulation cycles, which allows local guest OS users to cause a denial of service (guest OS crash) via unspecified operations on MMIO regions.

Xen 4.0 through 4.3.x, when using AVX or LWP capable CPUs, does not properly clear previous data from registers when using an XSAVE or XRSTOR to extend the state components of a saved or restored vCPU after touching other restored extended registers, which allows local guest OSes to obtain sensitive information by reading the registers.