A buffer overflow flaw was found, in versions from 2.6.34 to 5.2.x, in the way Linux kernel's vhost functionality that translates virtqueue buffers to IOVs, logged the buffer descriptors during migration. A privileged guest user able to pass descriptors with invalid length to the host when migration is underway, could use this flaw to increase their privileges on the host.
https://www.openwall.com/lists/oss-security/2019/09/17/1
https://www.debian.org/security/2019/dsa-4531
https://usn.ubuntu.com/4135-2/
https://usn.ubuntu.com/4135-1/
https://security.netapp.com/advisory/ntap-20191031-0005/
https://seclists.org/bugtraq/2019/Sep/41
https://seclists.org/bugtraq/2019/Nov/11
https://lists.debian.org/debian-lts-announce/2019/10/msg00000.html
https://lists.debian.org/debian-lts-announce/2019/09/msg00025.html
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-14835
https://access.redhat.com/errata/RHSA-2019:2924
https://access.redhat.com/errata/RHSA-2019:2901
https://access.redhat.com/errata/RHSA-2019:2900
https://access.redhat.com/errata/RHSA-2019:2899
https://access.redhat.com/errata/RHSA-2019:2889
https://access.redhat.com/errata/RHSA-2019:2869
https://access.redhat.com/errata/RHSA-2019:2867
https://access.redhat.com/errata/RHSA-2019:2866
https://access.redhat.com/errata/RHSA-2019:2865
https://access.redhat.com/errata/RHSA-2019:2864
https://access.redhat.com/errata/RHSA-2019:2863
https://access.redhat.com/errata/RHSA-2019:2862
https://access.redhat.com/errata/RHSA-2019:2854
https://access.redhat.com/errata/RHSA-2019:2830
https://access.redhat.com/errata/RHSA-2019:2829
https://access.redhat.com/errata/RHSA-2019:2828
https://access.redhat.com/errata/RHSA-2019:2827
https://access.redhat.com/errata/RHBA-2019:2824
http://www.openwall.com/lists/oss-security/2019/10/09/7
http://www.openwall.com/lists/oss-security/2019/10/09/3
http://www.openwall.com/lists/oss-security/2019/10/03/1
http://www.openwall.com/lists/oss-security/2019/09/24/1
http://www.huawei.com/en/psirt/security-advisories/huawei-sa-20200115-01-qemu-en
http://packetstormsecurity.com/files/154951/Kernel-Live-Patch-Security-Notice-LSN-0058-1.html
http://packetstormsecurity.com/files/154572/Kernel-Live-Patch-Security-Notice-LSN-0056-1.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00066.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00064.html