That's a misunderstanding. This is not a security vulnerability and Rust explicitly does not defend from malicious programs, only from mistakes. This bug however is quite dangerous, because unlike many soundness bugs it seems plausible to hit by mistake.
> it seems plausible to hit by mistake
The report seems to claim the opposite:
> Looking at the bug itself, it is also very likely that this unsoundness has not caused memory unsafety by accident. While it looks easy to trigger, to exploit this you need an intentionally malicious Drop implementation.