A flaw was found in the Linux kernel's implementation of biovecs in versions before 5.9-rc7. A zero-length biovec request issued by the block subsystem could cause the kernel to enter an infinite loop, causing a denial of service. This flaw allows a local attacker with basic privileges to issue requests to a block device, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
https://www.kernel.org/doc/html/latest/block/biovecs.html
https://usn.ubuntu.com/4576-1/
https://lists.debian.org/debian-lts-announce/2020/10/msg00034.html
https://lists.debian.org/debian-lts-announce/2020/10/msg00032.html
https://bugzilla.redhat.com/show_bug.cgi?id=1881424
http://www.openwall.com/lists/oss-security/2020/10/06/9
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00042.html
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00021.html