fs/namei.c in the Linux kernel before 5.5 has a may_create_in_sticky use-after-free, which allows local users to cause a denial of service (OOPS) or possibly obtain sensitive information from kernel memory, aka CID-d0cb50185ae9. One attack vector may be an open system call for a UNIX domain socket, if the socket is being moved to a new parent directory and its old parent directory is being removed.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.