CVE-2026-65665: Microsoft SharePoint Server Remote Code Execution Vulnerability

Overview

Severity
High (CVSS 8.8)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Remote Code Execution
Exploit Status
Not Exploited
Exploitation Likelihood
More Likely
Patch Tuesday
2026-Aug
Released
2026-08-11

Description

Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

FAQ

How could an attacker exploit the vulnerability? In a network-based attack, an authenticated attacker, as at least a Site Owner, could write arbitrary code to inject and execute code remotely on the SharePoint Server. 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.

Affected Products (2)

Microsoft Office

  • Microsoft SharePoint Server 2019
  • Microsoft SharePoint Server Subscription Edition

Security Updates (3)

Acknowledgments

<a href="https://www.linkedin.com/in/john-nzyuko-412b563b1/">John Nzyuko</a>, <a href="https://twitter.com/tuo4n8">tuo4n8</a> with <a href="https://vsrc.vng.com.vn/">Verichains Cyber Force</a>

Revision History

  • 2026-08-11: Information published.