CVE-2026-64900: Microsoft SharePoint Server Spoofing Vulnerability

Overview

Severity
High (CVSS 7.3)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
Category
Spoofing
Exploit Status
Not Exploited
Patch Tuesday
2026-Aug
Released
2026-08-11

Description

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.

FAQ

I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running? Yes. The same KB number applies to both SharePoint Server 2016 and SharePoint Enterprise Server 2016. Customers running either version should install the security update to be protected from this vulnerability. There are multiple update packages available for some of the affected software. Do I need to install all the updates listed in the Security Updates table for the software? Yes. Customers should apply all updates offered for the software installed on their systems. If multiple updates apply, they can be installed in any order. How could an attacker exploit this vulnerability? An authenticated attacker with permissions to add or modify content on an affected SharePoint page could store malicious script content in the page. The script could run in the security context of another user when that user views and interacts with the affected content, potentially allowing the attacker to access or modify SharePoint data available to that user.

Affected Products (3)

Microsoft Office

  • Microsoft SharePoint Enterprise Server 2016
  • Microsoft SharePoint Server 2019
  • Microsoft SharePoint Server Subscription Edition

Security Updates (5)

Revision History

  • 2026-08-11: Information published.