set_debugreg allows writes to reserved bits of the DR7 debug control register on x86-64. A malicious guest can cause the host to crash, leading to a DoS. If the vulnerable hypervisor is run on future hardware, the impact of the vulnerability might be widened depending on the future assignment of the currently-reserved debug register bits. All systems running 64-bit paravirtualised guests are vulnerable to this issue. 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.
Now public via: http://seclists.org/oss-sec/2012/q3/376
Created xen tracking bugs for this issue Affects: fedora-all [bug 854585]
xen-4.1.3-2.fc16 has been pushed to the Fedora 16 stable repository. If problems still persist, please make note of it in this bug report.