drivers/infiniband/core/ucma.c in the Linux kernel through 4.17.11 allows ucma_leave_multicast to access a certain data structure after a cleanup step in ucma_process_join, which allows attackers to cause a denial of service (use-after-free).
- https://usn.ubuntu.com/3797-2/
- https://usn.ubuntu.com/3847-2/
- https://github.com/ARPSyndicate/cvemon