Part 3/5:
The core issue stems from the deserialization of untrusted data within on-premises SharePoint servers. Deserialization, a process where data is converted back into an operable format, becomes a security risk when handled improperly. In this case, malicious actors can exploit this flaw to bypass security measures, execute arbitrary code, and potentially gain unauthorized access to sensitive organizational information.
By successfully exploiting this vulnerability, attackers can perform remote code execution — allowing them to run malicious scripts, steal data, or even take control of affected servers.