Description
It was found that the Xen hypervisor implementation as shipped with Red
Hat Enterprise Linux 5 did not properly restrict the syscall return
addresses in the sysret return path to canonical addresses. An unprivileged
user in a 64-bit para-virtualized guest, that is running on a 64-bit host
that has an Intel CPU, could use this flaw to crash the host or,
potentially, escalate their privileges, allowing them to execute arbitrary
code at the hypervisor level. (CVE-2012-0217, Important)
* It was found that guests could trigger a bug in earlier AMD CPUs, leading
to a CPU hard lockup, when running on the Xen hypervisor implementation. An
unprivileged user in a 64-bit para-virtualized guest could use this flaw to
crash the host. (CVE-2012-2934, Moderate)