In the Linux kernel, the following vulnerability has been resolved: bpf: Fix remap of arena. The bpf arena logic didn't account for mremap operation. Add a refcnt for multiple mmap events to prevent use-after-free in arena_vm_close.
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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.