The memory corruption would happen in the C code though. By the time that the program is actually affected by the memory error it could be much later, back in Rust code, and now you don't have any tools for debugging memory corruption because "that never happens in Rust".
Assuming you ever encounter the issue, sure. But this bug was only triggered by long keys, which are outside of the normal operating paradigms. So your Rust code calling into a C API would have had exactly the same security vulnerability as C++.
On the other hand, something like Java via JNI wouldn't, because it copies the data to a different address space as it goes through the language boundary. Horribly inefficient, but at least the C code only causes security issues in the C regions. By the time it gets back into Java it either crashes or it's safe again, no undefined behaviour leaks through the API boundary.