Description:
The mulDiv() function in OpenZeppelin's Math.sol (v5.1.0) uses a bitwise XOR (^) operator instead of exponentiation (**) in the calculation of the modular inverse:

This is incorrect as the intention appears to be exponentiation (squaring) rather than bitwise XOR. The XOR operation will produce incorrect results for the inverse calculation.

Impact:

• Incorrect calculation of modular inverse

• Potential security implications in functions relying on this calculation

• Could lead to incorrect results in any contract using this math utility

• High severity as it affects core mathematical operations

Recommended Mitigation:
Replace the XOR operator (^) with the exponentiation operator (**):

Likelihood and Impact

• Impact: High (mathematical correctness)

• Likelihood: Medium (always occurs when this code path is executed)

• Severity: HIGH