Language: Python
Label: safe
CWE: CWE-193 \u2014 Off-by-one Error
A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

Code:
    def __init__(self, value_type: VyperType, length: int):
        if not 0 < length < 2**256:
            raise InvalidType("Array length is invalid")

        if length >= 2**64:
            warnings.warn("Use of large arrays can be unsafe!")

        super().__init__(UINT256_T, value_type)
        self.length = length