The function get_page_from_gfn does not validate its input GFN. An invalid GFN passed to a hypercall which uses this function will cause the hypervisor to read off the end of the frame table and potentially crash. A malicious PV guest administrator can cause Xen to crash. If the out of bounds access does not lead to a crash, a carefully crafted privilege escalation cannot be excluded, even though the guest doesn't itself control the values written. Acknowledgements: Red Hat would like to thank the Xen project for reporting this issue.
Statement: Not vulnerable. This issue did not affect the versions of the kernel-xen package as shipped with Red Hat Enterprise Linux 5. This issue did not affect Red Hat Enterprise Linux 6 and Red Hat Enterprise MRG as we did not have support for Xen hypervisor.
Created xen tracking bugs for this issue Affects: fedora-all [bug 883094]
xen-4.2.0-6.fc18 has been pushed to the Fedora 18 stable repository. If problems still persist, please make note of it in this bug report.