The root of this problem seems to be the widespread availability of 64-bit CPUs. ≥ When this code was first written, most processors had 32-bit registers and 4

The root of this problem seems to be the widespread availability of 64-bit CPUs. ≥ When this code was first written, most processors had 32-bit registers and 4GB of addressable memory, so allocating 1GB strings as input was impractical. Now that 64-bit processors are quite common, allocating such large strings is feasible and the vulnerable conditions are reachable. One has to wonder how much code written in the past 30 years has safety checks assuming 32-bit processors which now have vulnerabilities like this one. I'd bet quite a lot.