CVE-2018-12893

An issue was discovered in Xen through 4.10.x. One of the fixes in XSA-260
added some safety checks to help prevent Xen livelocking with debug
exceptions. Unfortunately, due to an oversight, at least one of these
safety checks can be triggered by a guest. A malicious PV guest can crash
Xen, leading to a Denial of Service. All Xen systems which have applied the
XSA-260 fix are vulnerable. Only x86 systems are vulnerable. ARM systems
are not vulnerable. Only x86 PV guests can exploit the vulnerability. x86
HVM and PVH guests cannot exploit the vulnerability. An attacker needs to
be able to control hardware debugging facilities to exploit the
vulnerability, but such permissions are typically available to unprivileged
users.

Notes