Earlier quoted context omitted.
Agreed! Just one quibble: the reporter was anonymous, so they aren't doing it for prestige. Perhaps it's griefing?
Good point. Reading the text, it also seems hard for MITRE to set general rules for when undefined memory access is a vulnerability. Here it is not exploitable because it is only in a debug build and because the accessed memory is out-of-bounds in the intended context, but provably always within the memory bounds that are readable by curl, if I understand correctly. For a case like this, it is easy to imagine this be…
That doesn't tell the whole story in C code, though. Out-of-bounds access is UB, thus the whole branch could be assumed to be never taken and optimized out by an enterprising compiler. In this case it will only cause missing characters in console output, but "will at worst cause a crash" is not entirely true.