the second require checking should be index<len instead of index<=len.
Impact Details
While this bug does not result in direct financial losses or value reduction, it does impact the contract's ability to deliver its promised functionality accurately. This type of issue falls within the scope of "Failing to deliver promised returns" in terms of functional expectations, even if not in a financial sense. The severity is moderate, as it affects usability and reliability without compromising funds or causing direct losses.
References
none
Proof of concept
Proof of Concept
result:
As you can see, test1 passed, but test2 failed. but they should share same revert code.