FOSS is not immune to software vulnerabilities. In fact, clever ABCs have probably seeded "in plain sight" exploits that compromise a user without tainting the open source code. This is the reality we are working with.
Discussion
Yes, and I think this is especially a risk with something like nostr. When it comes to security and privacy, the worst implementation in use sets the standard. Luckily, there's limited damage you can do to users on nostr.