The mq_notify function in the Linux kernel through 4.11.9 does not set the sock pointer to NULL upon entry into the retry logic. During a user-space close of a Netlink socket, it allows attackers to cause a denial of service (use-after-free) or possibly have unspecified other impact.
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f991af3daabaecff34684fd51fac80319d1baad1
www.debian.org/security/2017/dsa-3927
www.debian.org/security/2017/dsa-3945
www.securityfocus.com/bid/99919
access.redhat.com/errata/RHSA-2017:2918
access.redhat.com/errata/RHSA-2017:2930
access.redhat.com/errata/RHSA-2017:2931
access.redhat.com/errata/RHSA-2018:0169
access.redhat.com/errata/RHSA-2018:3822
github.com/torvalds/linux/commit/f991af3daabaecff34684fd51fac80319d1baad1
help.ecostruxureit.com/display/public/UADCE725/Security+fixes+in+StruxureWare+Data+Center+Expert+v7.6.0
www.exploit-db.com/exploits/45553/