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.
Status:
- Force netlink_attachskb() to return 1
- Unblock the exploit thread
- Force the second fget() call to return NULL
- Create the exploit
Reference: A step-by-step Linux Kernel exploitation