Based on the description, it is inferred that a flaw in Microsoft Office SharePoint’s authentication logic allows an attacker without valid credentials to bypass a built‑in security feature over the network. The weakness is categorized as CWE‑1390 and carries a CVSS score of 9.1, indicating a high‑impact vulnerability that could lead to unauthorized access or privilege escalation if exploited. The attack path requires network connectivity to the SharePoint server and an attacker capable of sending crafted authentication requests, but does not rely on local user privileges.

Microsoft SharePoint Enterprise Server 2016, SharePoint Server 2019 and SharePoint Server Subscription Edition are all affected by this weakness. No specific version numbers are listed, so all current releases of these products should be considered vulnerable until Microsoft addresses the issue in an update.

The EPSS score of 2% indicates that although the flaw is severe, it is less likely to be widely exploited at this time. Based on the description, it is inferred that the vulnerability can be exploited by connecting to the SharePoint server over the network, crafting an authentication request that exploits the weak validation logic, and then leveraging the bypassed security feature to gain unauthorized access to protected data or functionality. The high CVSS rating reflects the potential for significant confidentiality, integrity, and availability impact once the bypass is achieved.