Skip to content
AI Security

Interview question · Application & API Security

You are reviewing an API's CORS configuration that allows credentials. What mistakes do you look for, and what is the safe pattern?

CORS never blocks a request from being sent. It decides whether another site's script may read the answer, and with credentials allowed, that answer contains the logged-in user's data.

mediumNewPreparation tags: Google, Microsoft, MetaUpdated Nov 2026

CORS never blocks a request from being sent. It decides whether another site's script may read the answer, and with credentials allowed, that answer contains the logged-in user's data.

Make your first attempt

What would you say before reading the answer?

  1. 01 State the assumptions your answer depends on.
  2. 02 Explain the mechanism and choose a control.
  3. 03 Name a condition that would change your decision.

The worked answer includes an approach, scoring criteria and follow-up questions. Compare the reasoning with your own.

10 answers per topic instead of 5, plus saved progress and bookmarks · costs nothingor unlock all 529 remaining answers · $25

Every worked answer in all 17 topics, every lesson in every course, the full concept curriculum, the complete practice-test bank, and the downloadable security field guides.

6 months · One payment · No auto-renewal

What if · the follow-ups in this answer

The answer works through 6 follow-ups like an interviewer would

An API sets Access-Control-Allow-Credentials true and reflects whatever Origin header the request carries.

  1. Why is this configuration dangerous?
  2. Which origin checks are also unsafe?
  3. How should the allowlist work?
  4. Does the API need credentialed CORS at all?
  5. How would you test it?
  6. What would you change?

Each rung has a nudge, a model answer, the principle that carries over and the weak answer to avoid. Premium opens every answer and ladder.

UP NEXT ON YOUR JOURNEY
Next in this trackWhat changed in the OWASP Top 10:2025 for web applications, and how would you use it in an AppSec programme?Next in this trackDesign the login, MFA and account recovery flows for a consumer web app that attackers target with credential stuffing.Next in this trackA gift card can be redeemed twice if two requests arrive at the same moment. Explain the bug class and fix it properly.
DISCUSSION · 0

No comments yet. Share a correction or a different way to answer it.