I was using Harmonic for Hacker News (https://play.google.com/store/apps/details?id=com.simon.harm...), so it's possible the issue was with the app rather than HN itself.
I later found a separate submission (https://news.ycombinator.com/item?id=50399587) in New that had received some votes but hadn't generated any discussion.
Regardless, this isn't the first time researchers have explored TCP port 0, and it certainly won't be the last.
A few examples from a quick Google search:
* https://www.cyber-threat-intelligence.com/publications/IFIPN...
* https://z3r0trust.medium.com/socket-programming-the-bizarre-...
* https://arxiv.org/pdf/2004.03653
None of these earlier publications diminish the value of the current research. If anything, they highlight how easily lessons involving obscure protocol behaviors and edge cases can be overlooked or forgotten.
Personally, I find network stack manipulation a particularly interesting area of security research, and one that doesn't always receive the attention it deserves. There's understandably significant focus on application-layer vulnerabilities, but that emphasis can lead us to take the behavior and security of the underlying network stack for granted.
The TCP/IP stack is mature, but maturity shouldn't be confused with an absence of exploitable behavior. Between implementation differences, ambiguous specifications, legacy protocol assumptions, and unexpected interactions across layers, there are undoubtedly more edge cases, vulnerabilities, and attack surfaces worth investigating.