FreeBSD : xen-kernel -- x86 segment base write emulation lacking canonical address checks (53dbd096-ba4d-11e6-ae1b-002590263bf5)
Medium Nessus Plugin ID 95507
SynopsisThe remote FreeBSD host is missing a security-related update.
DescriptionThe Xen Project reports :
Both writes to the FS and GS register base MSRs as well as the WRFSBASE and WRGSBASE instructions require their input values to be canonical, or a #GP fault will be raised. When the use of those instructions by the hypervisor was enabled, the previous guard against #GP faults (having recovery code attached) was accidentally removed.
A malicious guest administrator can crash the host, leading to a DoS.
SolutionUpdate the affected package.