There is a use-after-free vulnerability in the Linux kernel through 5.5.2 in the vgacon_invert_region function in drivers/video/console/vgacon.c.
https://www.debian.org/security/2020/dsa-4698
https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html
https://lists.debian.org/debian-lts-announce/2020/06/msg00012.html
https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html
https://bugzilla.kernel.org/show_bug.cgi?id=206357
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00039.html