The 5 Most Common API Vulnerabilities in 2026

Based on 42Crunch's State of API Security 2026 report analyzing 200 real-world production vulnerabilities from 2024–2025, the five most common API vulnerabilities are: broken authentication (23.5%), broken object-level authorization or BOLA (12.5%), broken object property-level authorization or BOPLA (12.5%), broken functional-level authorization or BFLA (10.5%), and security misconfiguration (5%). Authorization flaws dominate the landscape, with attackers commonly exploiting identifier manipulation, endpoint enumeration, and malicious inputs like SQL injection and SSRF. Recommended mitigations include enforcing OAuth-based authentication, maintaining an API inventory, applying least-privilege authorization checks per endpoint, and enforcing strict input validation.