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."

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 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.