How Did the DAO Hack Relate to Integer Overflow?

The infamous DAO hack of 2016 was primarily a reentrancy attack, not an integer overflow. However, integer overflow vulnerabilities were a significant security concern in early Solidity.

While the DAO attack itself exploited the call.value() function's gas limit and the lack of the CEI pattern, the awareness of overflow/underflow issues was high at the time. The widespread use of SafeMath was a direct response to preventing the potential for balance manipulation via integer vulnerabilities, which were a separate, major class of bug.