The aio_aqueue function, used by the lio_listio system call, fails to release a reference to a credential in an error case. An attacker may cause the reference count to overflow, leading to a use after free (UAF).
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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.