XSS Vulnerability in Address Validation

[rsisco]

Steps to reproduce:

• Log into an existing account on a site with AvaTax address validation enabled
• Click Address Book > Add New Address
• Complete the address form with the following value in one of the address fields:
  "><script>alert('XSS')</script>
• Click Save Address

Expected result:
Either the address will be saved or a modal will display suggesting an alternative address or reporting that the address couldn't be verified:

Actual result:
The injected script is executed, resulting in a pop-up window:

[rsisco]

This has been fixed in version 1.1.3 of this extension via PR #75.