Uninitialized memory access in Motoko incremental garbage collector

Motoko's incremental garbage collector is impacted by an uninitialized memory access bug, caused by incorrect use of write barriers in a few locations. This vulnerability could potentially allow unauthorized read or write access to a Canister's memory. However, exploiting this bug requires the Canister to enable the incremental garbage collector or enhanced orthogonal persistence, which are non-default features in Motoko.