btrfs_root_node in fs/btrfs/ctree.c in the Linux kernel through 5.3.12 allows a NULL pointer dereference because rcu_dereference(root->node) can be zero.
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00021.html
https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19036
https://security.netapp.com/advisory/ntap-20191205-0001/
Source: MITRE
Published: 2019-11-21
Updated: 2020-08-03
Type: CWE-476
Base Score: 4.3
Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 5.5
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 1.8
Severity: MEDIUM