(Pwn2Own) Microsoft SharePoint ValidateTokenIssuer Improper Verification of Cryptographic Signature Authentication Bypass Vulnerability

This vulnerability allows remote attackers to bypass authentication on affected installations of Microsoft SharePoint. Authentication is not required to exploit this vulnerability. The specific flaw exists within the ValidateTokenIssuer method. The issue results from the lack of proper verification of a cryptographic signature. An attacker can leverage this vulnerability to bypass authentication on the system.