arch/x86/x86_emulate/x86_emulate.c in Xen 3.2.1 through 4.4.x does not properly check privileges, which allows local HVM guest users to gain privileges or cause a denial of service (crash) via a crafted (1) CALL, (2) JMP, (3) RETF, (4) LCALL, (5) LJMP, or (6) LRET far branch instruction.

The x86_emulate function in arch/x86/x86_emulate/x86_emulate.c in Xen 4.4.x and earlier does not properly check supervisor mode permissions, which allows local HVM users to cause a denial of service (guest crash) or gain guest kernel mode privileges via vectors involving an (1) HLT, (2) LGDT, (3) LIDT, or (4) LMSW instruction.

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.

Multiple integer overflows in unspecified suboperations in the flask hypercall in Xen 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-2014-1893.

Multiple integer overflows in the (1) FLASK_GETBOOL, (2) FLASK_SETBOOL, (3) FLASK_USER, and (4) FLASK_CONTEXT_TO_SID 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.

Multiple integer overflows in the (1) FLASK_GETBOOL and (2) FLASK_SETBOOL 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.

Xen, possibly before 4.0.2, allows local 64-bit PV guests to cause a denial of service (host crash) by specifying user mode execution without user-mode pagetables.

Xen 3.0.3 through 4.1.x (possibly 4.1.6.1), 4.2.x (possibly 4.2.3), and 4.3.x (possibly 4.3.1) does not properly prevent access to hypercalls, which allows local guest users to gain privileges via a crafted application running in ring 1 or 2.

The outs instruction emulation in Xen 3.1.x, 4.2.x, 4.3.x, and earlier, when using FS: or GS: segment override, uses an uninitialized variable as a segment base, which allows local 64-bit PV guests to obtain sensitive information (hypervisor stack content) via unspecified vectors related to stale data in a segment register.

Off-by-one error in the __addr_ok macro in Xen 3.3 and earlier allows local 64 bit PV guest administrators to cause a denial of service (host crash) via unspecified hypercalls that ignore virtual-address bits.