Buffer overflow

Buffer overflow is when a computer program gets more data than it was expecting. This extra data fills up the program’s memory, causing it to crash or take control of the computer. It’s kind of like filling up a bucket with water—if you put too much water in the bucket, it overflows!

Related topics others have asked about:

Billion laughs, Buffer over-read, Coding conventions, Computer security, End-of-file, Heap overflow, Ping of death, Port scanner, Return-to-libc attack, Safety-critical system, Security-focused operating system, Self-modifying code