Glossary
Integer Overflow
A bug where an arithmetic operation produces a value too large (or too small) for its fixed-size type, wrapping around — historically a common Solidity exploit.
Solidity ≤ 0.7 used wrapping arithmetic by default: uint256 plus
1 from its max value silently wrapped to zero. A balance of 0
minus 1 wrapped to 2^256 - 1. Several early DEX and token
exploits — the 2018 BeautyChain / BEC hack being the most famous —
hinged on this behavior.
Solidity 0.8 made arithmetic checked by default: any overflow or
underflow reverts. The risk has not disappeared — assembly, low-
level libraries, and the explicit unchecked block can still
overflow — but classic overflow exploits are now rare in modern
code.