Business Logic Flaws: The Silent Threat in Modern Web Applications
Security Boulevard, Thursday, April 16th, 2026
In late 2019, something unusual happened on Robinhood. Users discovered what the internet quickly labeled the 'infinite money glitch'. It wasn't a zero-day exploit. There was no malware involved. No one bypassed authentication or cracked encryption.
Instead, users found a flaw in how the platform calculated buying power during options trading.
Here's what unfolded.
Some users deposited a small amount of money. They used margin to buy options contracts. Then they noticed something subtle: The system treated certain option positions as if they offset risk in a way that increased their available buying power. Even though the real exposure hadn't actually decreased.
By repeating variations of this sequence, users were suddenly controlling positions worth hundreds of thousands of dollars while holding only a few thousand dollars in actual capital.
The code worked exactly as written.
The inputs were valid.
The API calls were legitimate.