PHP2Shell and the Math of Vibe Coding Your Own Software
· 16 min read

The value proposition from vibe coding businesses and LLM developers is that everyone will be able to make their own software easily. PHP2Shell, the pair of critical PHP flaws patched on October 21, 2026, is a good reminder that there is a lot more to the software industry than the creation of the initial software. I put the published numbers into a simple model. In that model, shared open source costs roughly 2,000 times less than a world where every user writes their own copy. LLMs do not close that gap except for very small pieces of code.
