Zig's approach to memory safety is an open question. I don't like it (obviously, a very subjective statement), but as more software is written in it, we'll get empirical data about whether Zig's bet pays off. It very well might.
This matches my experience with the runtimes in question—I tried Bun out for a very small project and ran into 3 distinct crashes, often in very simple parts of the code like command line processing. Obviously not every crash / null-pointer dereference is a memory safety issue, but I think most people would agree that Zig does not seem to make bug-free software easier to write.
Probably segfaults imply the absence of memory safety.