The hypervisor_callback function in Xen, possibly before 3.4.0, as applied to the Linux kernel 2.6.30-rc4, 2.6.18, and probably other versions allows guest user applications to cause a denial of service (kernel oops) of the guest OS by triggering a segmentation fault in "certain address ranges."

A module in Roxen 2.0 before 2.0.92, and 2.1 before 2.1.264, does not properly decode UTF-8, Mac and ISO-2202 encoded URLs, which could allow a remote attacker to execute arbitrary commands or view arbitrary files via an encoded URL.