This update for xen to version 4.9.2 fixes several issues.
This feature was added:
Added script, udev rule and systemd service to watch for vcpu online/offline
events in a HVM domU. They are triggered via 'xl vcpu-set domU N'
These security issues were fixed:
CVE-2018-8897: Prevent mishandling of debug exceptions on x86 (XSA-260, bsc#1090820)
Handle HPET timers in IO-APIC mode correctly to prevent malicious or buggy
HVM guests from causing a hypervisor crash or potentially privilege
escalation/information leaks (XSA-261, bsc#1090822)
Prevent unbounded loop, induced by qemu allowing an attacker to permanently
keep a physical CPU core busy (XSA-262, bsc#1090823)
CVE-2018-10472: x86 HVM guest OS users (in certain configurations) were able
to read arbitrary dom0 files via QMP live insertion of a CDROM, in conjunction
with specifying the target file as the backing file of a snapshot
(bsc#1089152).
CVE-2018-10471: x86 PV guest OS users were able to cause a denial of service
(out-of-bounds zero write and hypervisor crash) via unexpected INT 80
processing, because of an incorrect fix for CVE-2017-5754 (bsc#1089635).
CVE-2018-7540: x86 PV guest OS users were able to cause a denial of service
(host OS CPU hang) via non-preemptable L3/L4 pagetable freeing (bsc#1080635).
CVE-2018-7541: Guest OS users were able to cause a denial of service
(hypervisor crash) or gain privileges by triggering a grant-table transition
from v2 to v1 (bsc#1080662).
CVE-2018-7542: x86 PVH guest OS users were able to cause a denial of service
(NULL pointer dereference and hypervisor crash) by leveraging the mishandling
of configurations that lack a Local APIC (bsc#1080634).
These non-security issues were fixed:
bsc#1087252: Update built-in defaults for xenstored in stubdom, keep default
to run xenstored as daemon in dom0
bsc#1087251: Preserve xen-syms from xen-dbg.gz to allow processing vmcores
with crash(1)