Common Security Issues in Implementing OAuth 2.0 and How to Mitigate Them

This post reviews common OAuth 2.0 security pitfalls—including insecure token storage, redirect URI manipulation, CSRF in OAuth flows, IDOR via access tokens, insufficient scope validation, and the risks of the implicit grant—and provides practical mitigation guidance and code snippets (secure cookies, redirect validation, state tokens, scope checks, and recommending PKCE). It emphasizes adopting best practices and regular review to maintain secure OAuth implementations.