> For the complete documentation index, see [llms.txt](https://doc.auditx.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.auditx.net/auditx-ecosystem/services/types-of-vulnerabilities-detected/integer-overflows-underflows.md).
# Integer Overflows/Underflows
**Integer Overflows** and **Underflows** occur when mathematical operations exceed the storage limits of a variable, causing unexpected behavior. These vulnerabilities allow attackers to manipulate values in ways that can break contract logic.
**Integer Overflows** and **Underflows** occur when mathematical operations exceed the storage limits of a variable, causing unexpected behavior. These vulnerabilities allow attackers to manipulate values in ways that can break contract logic.
#### **How They Work**
1. **Integer Overflow:** When a value exceeds the maximum limit of its data type, it wraps around to the minimum value. Example:
```
solidity
uint8 x = 255; // Max value for uint8
x += 1; // Overflow: x becomes 0
```
2. **Integer Underflow:** When a value is reduced below the minimum limit of its data type, it wraps around to the maximum value. Example:
```
solidity
uint8 x = 0; // Min value for uint8
x -= 1; // Underflow: x becomes 255
```
#### **Real-Life Impact**
Attackers exploit overflows/underflows to:
* Mint extra tokens.
* Bypass balance checks.
* Gain unauthorized access to funds.
---
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