The vulnerability arises from deserialization of untrusted data in Microsoft Office SharePoint, enabling an authorized attacker with existing credentials to execute code remotely. This flaw is classified as CWE-1220 and can lead to full control over the SharePoint server, jeopardizing confidentiality, integrity, and availability of the entire environment.

Microsoft SharePoint Enterprise Server 2016, SharePoint Server 2019, and SharePoint Subscription Edition are affected. Any installation of these products that has not received the relevant security update is vulnerable, regardless of deployment environment or governance model.

The CVSS score of 8.8 indicates high severity. The EPSS score of 0.00071 indicates a very low probability of exploitation, and the vulnerability is not listed in CISA’s KEV catalog. Based on the description, the likely attack vector is over a network from an attacker who already holds authorized credentials but can exploit overly permissive access. Exploitation requires the attacker to interact with vulnerable components, which may limit the threat to internal or compromised accounts rather than the general public.