arch/ia64/xen/faults.c in Xen 3.4 and 4.0 in Linux kernel 2.6.18, and possibly other kernel versions, when running on IA-64 architectures, allows local users to cause a denial of service and "turn on BE by modifying the user mask of the PSR," as demonstrated via exploitation of CVE-2006-0742.

Description of problem:

The recent fix to validate the frontend's frame buffer description neglected to limit the frame buffer size correctly. This lets a malicious frontend make the backend attempt to map an arbitrary amount of guest memory, which could be useful for a denial of service attack against dom0.

Proposed upstream patch:

http://xenbits.xensource.com/xen-unstable.hg?rev/9044705960cb30cec385bdca7305bcf7db096721

Buffer overflow in the backend framebuffer of XenSource Xen Para-Virtualized Framebuffer (PVFB) Message 3.0 through 3.0.3 allows local users to cause a denial of service (SDL crash) and possibly execute arbitrary code via "bogus screen updates," related to missing validation of the "format of messages."

Buffer overflow in the backend of XenSource Xen Para Virtualized Frame Buffer (PVFB) 3.0 through 3.1.2 allows local users to cause a denial of service (crash) and possibly execute arbitrary code via a crafted description of a shared framebuffer.