This article is focused on providing clear, simple, actionable guidance for providing Input Validation security functionality in your applications. It is not the primary method of preventing XSS, SQL Injection and other attacks but can significantly contribute to reducing their impact if implemented properly. Data from all potentially untrusted sources should be subject to input validation, including not only Internet-facing web clients but also backend feeds over extranets. It can be used to detect unauthorized input before it is processed by the application.”]
Source: https://cheatsheetseries.owasp.org/cheatsheets/Input_Validation_Cheat_Sheet.html