"The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array." - Entry from the Common Weakness Enumeration
For more info visit <a href="https://cwe.mitre.org/data/definitions/129.html" target="_blank" rel="noopener noreferrer">CWE-129</a>