In the Linux kernel 5.4.0-rc2, there is a use-after-free (read) in the __blk_add_trace function in kernel/trace/blktrace.c (which is used to fill out a blk_io_trace structure and place it in a per-cpu sub-buffer).
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00039.html
https://bugzilla.kernel.org/show_bug.cgi?id=205711
https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html
https://lists.debian.org/debian-lts-announce/2020/06/msg00012.html
https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html
https://security.netapp.com/advisory/ntap-20200103-0001/
https://usn.ubuntu.com/4342-1/
https://usn.ubuntu.com/4344-1/
https://usn.ubuntu.com/4345-1/
Source: MITRE
Published: 2019-12-12
Updated: 2020-06-10
Type: CWE-416
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH