"Pay Whatever You Want": The High Cost of Missing Server-Side Validation

This vulnerability highlights a critical failure in e-commerce security where servers blindly trust client-provided pricing data. It serves as a stark reminder that all business logic, especially financial calculations, must be strictly validated server-side to prevent trivial exploitation via intercepting proxies. Developers must ensure that sensitive values like order totals are recalculated from trusted database records rather than accepted from the frontend.