Blind Dynamic Allocator Exploitation

The field of dynamic allocator exploitation appears to be as dynamic as the allocators themselves. Whenever a new PoC showcasing a particularly effective abuse of the dynamic allocator is patched, fresh methods of heap exploitation emerge. After the introduction of safelinking, it was widely believed that leakless heap exploitation had been permanently eliminated from the hacking landscape. It was stated that a successful exploit requires at least two different vulnerabilities. Yet is this really the case?