We don't use realloc directly, and very little malloc anyways.
It is most likely a std container failing to get enough memory. The issue isn't so much that the addressing failed but whether it is because it ran out of RAM or it was passed a bad ptr. If this is happening in a std container, which we rely heavily upon, then it's the former.
Did the issue happen after scanning the whole chain or was it in a freshly started process?