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Glossary Term

API Schema Validation Failure

Missing or weak schema checks let APIs accept payload shapes they never intended, opening business logic bypasses.

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API Schema Validation Failure

1-minute read

What it is

An API Schema Validation Failure happens when an API does not properly check the structure of incoming or outgoing data, allowing unexpected information to pass through.

Why it matters

If an API accepts data it shouldn’t, attackers may be able to bypass restrictions, access extra information, or trigger actions that were not intended to be available publicly.

How to reduce risk

  • Clearly define what data your API should accept
  • Block unknown or unnecessary fields
  • Regularly review public APIs for unexpected behaviour

External resources

  • https://owasp.org/API-Security/
  • https://cheatsheetseries.owasp.org/cheatsheets/REST_Security_Cheat_Sheet.html