Xen 4.2.x and 4.1.x does not properly restrict access to IRQs, which allows local stub domain clients to gain access to IRQs and cause a denial of service via vectors related to "passed-through IRQs or PCI devices."
qemu-nbd in QEMU, as used in Xen 4.2.x, determines the format of a raw disk image based on the header, which allows local guest OS administrators to read arbitrary files on the host by modifying the header to identify a different format, which is used when the guest is restarted, a different vulnerability than CVE-2008-2004.
Xen 4.2.x, 4.1.x, and earlier, when the hypervisor is running "under memory pressure" and the Xen Security Module (XSM) is enabled, uses the wrong ordering of operations when extending the per-domain event channel tracking table, which causes a use-after-free and allows local guest kernels to inject arbitrary events and gain privileges via unspecified vectors.
oxenstored in Xen 4.1.x, Xen 4.2.x, and xen-unstable does not properly consider the state of the Xenstore ring during read operations, which allows guest OS users to cause a denial of service (daemon crash and host-control outage, or memory consumption) or obtain sensitive control-plane data by leveraging guest administrative access.
The do_hvm_op function in xen/arch/x86/hvm/hvm.c in Xen 4.2.x on the x86_32 platform does not prevent HVM_PARAM_NESTEDHVM (aka nested virtualization) operations, which allows guest OS users to cause a denial of service (long-duration page mappings and host OS crash) by leveraging administrative access to an HVM guest in a domain with a large number of VCPUs.
The AMD IOMMU support in Xen 4.2.x, 4.1.x, 3.3, and other versions, when using AMD-Vi for PCI passthrough, uses the same interrupt remapping table for the host and all guests, which allows guests to cause a denial of service by injecting an interrupt into other guests.
Xen 4.2.x, 4.1.x, and 4.0, when using Intel VT-d for PCI passthrough, does not properly configure VT-d when supporting a device that is behind a legacy PCI Bridge, which allows local guests to cause a denial of service to other guests by injecting an interrupt.
Memory leak in Xen 4.2 and unstable allows local HVM guests to cause a denial of service (host memory consumption) by performing nested virtualization in a way that triggers errors that are not properly handled.
The pciback_enable_msi function in the PCI backend driver (drivers/xen/pciback/conf_space_capability_msi.c) in Xen for the Linux kernel 2.6.18 and 3.8 allows guest OS users with PCI device access to cause a denial of service via a large number of kernel log messages. NOTE: some of these details are obtained from third party information.
The get_page_type function in xen/arch/x86/mm.c in Xen 4.2, when debugging is enabled, allows local PV or HVM guest administrators to cause a denial of service (assertion failure and hypervisor crash) via unspecified vectors related to a hypercall.