Multiple race conditions in the ext4 filesystem implementation in the Linux kernel before 4.5 allow local users to cause a denial of service (disk corruption) by writing to a page that is associated with a different user's file after unsynchronized hole punching and page-fault handling.
https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html
https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html
https://github.com/torvalds/linux/commit/ea3d7209ca01da209cda6f0dea8be9cc4b7a933b
https://bugzilla.redhat.com/show_bug.cgi?id=1323577
https://access.redhat.com/errata/RHSA-2017:2669
https://access.redhat.com/errata/RHSA-2017:2077
https://access.redhat.com/errata/RHSA-2017:1842
http://www.ubuntu.com/usn/USN-3007-1
http://www.ubuntu.com/usn/USN-3006-1
http://www.ubuntu.com/usn/USN-3005-1
http://www.securitytracker.com/id/1035455
http://www.securityfocus.com/bid/85798