In net/socket.c in the Linux kernel through 4.17.1, there is a race condition between fchownat and close in cases where they target the same socket file descriptor, related to the sock_close and sockfs_setattr functions. fchownat does not increment the file descriptor reference count, which allows close to set the socket to NULL during fchownat's execution, leading to a NULL pointer dereference and system crash.
http://www.securityfocus.com/bid/104453
https://access.redhat.com/errata/RHSA-2018:2948
https://github.com/torvalds/linux/commit/6d8c50dcb029872b298eea68cc6209c866fd3e14
https://lkml.org/lkml/2018/6/5/14
https://patchwork.ozlabs.org/patch/926519/
https://usn.ubuntu.com/3752-1/
Source: MITRE
Published: 2018-06-12
Updated: 2018-10-31
Type: CWE-362
Base Score: 7.1
Vector: AV:N/AC:M/Au:N/C:N/I:N/A:C
Impact Score: 6.9
Exploitability Score: 8.6
Severity: HIGH
Base Score: 5.9
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 2.2
Severity: MEDIUM