memoffset allows attempt of reading data from address 0 with arbitrary type. This behavior is an undefined behavior because address 0 to std::mem::size_of<T> may not have valid bit-pattern with T. Old implementation dereferences uninitialized memory obtained from std::mem::align_of. Older implementation prior to it allows using uninitialized data obtained from std::mem::uninitialized with arbitrary type then compute offset by taking the address of field-projection. This may also result in an undefined behavior for "father" that includes (directly or transitively) type that does not allow to be uninitialized.

This flaw was corrected by using std::ptr::addr_of in Gilnaa/memoffset#50.

References

• Gilnaa/memoffset#24
• Gilnaa/memoffset#50
• https://rustsec.org/advisories/RUSTSEC-2023-0045.html