Nick Woodhead had to scramble in response to a security flaw that threatened the majority of the world's websites. Courtesy of Nick Woodhead

This is an as-told-to essay based on a conversation with Nick Woodhead, founder of the AI company GPTree and chief technology officer at Rothco and Compubox. He spoke with Business Insider on Thursday to share how he's responded to vulnerabilities in the PHP programming language that could affect the majority of the world's websites. The following has been edited for brevity and clarity.

It's always a nightmare when these things happen. Since Tuesday evening, I haven't slept. It's coming close to 48 hours working on this. I'm a CTO, but I also run an agency for multiple clients and have my own company with my own product. So, balancing my time to get everything updated — it's just been exhausting.

About 70% of the internet runs on a programming language called PHP.…