A flaw was found in the Linux Kernel in the ucma_leave_multicast() function in drivers/infiniband/core/ucma.c which allows access to a certain data structure after freeing it in ucma_process_join(). This allows an attacker to cause a use-after-free bug and to induce kernel memory corruption, leading to a system crash or other unspecified impact. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is unlikely.