An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x. Guest OS users can cause a denial of service (host OS hang) via a high rate of events to dom0, aka CID-e99502f76271.
https://xenbits.xen.org/xsa/advisory-332.html
https://security.gentoo.org/glsa/202011-06
https://lists.debian.org/debian-lts-announce/2020/12/msg00027.html
https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html
https://github.com/torvalds/linux/commit/e99502f76271d6bc4e374fe368c50c67a1fd3070
http://www.openwall.com/lists/oss-security/2021/01/19/6
http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00025.html
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00075.html