Authentication & Access Control

Race Conditions

Learn how sending simultaneous requests exploits TOCTOU flaws — redeeming coupons multiple times, buying out-of-stock items, and bypassing rate limits.

Intermediate45 min6 lessons1 hands-on

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First lesson free. The full module is part of Pro.

You'll be able to

✓Understand TOCTOU vulnerabilities and why timing creates exploitable windows
✓Exploit race conditions to bypass single-use limits and discount codes
✓Use concurrent requests to trigger double-spend and limit bypass
✓Detect race condition vulnerabilities in transactional endpoints

Lessons

1How a Researcher Got $1,000 of Free Stock with 30 Parallel Requests
2Exploiting Race Conditions — Parallel Requests
3Race Windows — Finding and Maximizing Your Exploit
4Mini Lab — Read the Race Output
5Your Turn: Win the RaceHANDS-ON
6Module quiz

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