Issue 286: The APISecurity.io Top 5 API Vulnerabilities in 2025
Brief
This week, in our final 2025 issue of APISecurity. io, we look back at the five most frequent API vulnerabilities covered in the newsletter over the past 12 months. These issues highlight common mistakes teams make in API development and can help to spotlight where security efforts can deliver the biggest opportunity to reduce risk.
I’d like to wish all APISecurity. io followers the very best for the year ahead. No doubt we’ll have plenty more API security news and challenges to cover in 2026!
Vulnerability #1: Missing Authentication
Our most frequent API vulnerability this year was Missing Authentication . These are APIs that do not enforce authentication for sensitive operations, allowing anonymous users to access data or perform actions that should be restricted to authenticated users.
In 2024, this was our fifth most reported vulnerability.