SRC-2021-0016 : Microsoft SharePoint Server InputFormRegularExpressionValidator Denial of Service Vulnerability

Vulnerability Details:

This vulnerability allows remote attackers to cause a denial of service on affected installations of SharePoint Server. Authentication is required to exploit this vulnerability.

The specific flaw exists within the InputFormRegularExpressionValidator class. The issue results from the lack of proper validation of the user-supplied ValidationExpression property. An attacker can leverage this vulnerability to cause a regular expression denial of service.

Affected Vendors:

Microsoft

Affected Products:

SharePoint Server

Vendor Response:

Microsoft has issued an update to correct this vulnerability. More details can be found at: <https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-28450&gt;