CVE-2026-88166: Microsoft Office SharePoint 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
Less Likely
Patch Tuesday
2026-Oct
Released
2026-10-13

Description

Integer overflow or wraparound in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

FAQ

Is the Preview Pane an attack vector for this vulnerability? No, the Preview Pane is not an attack vector. 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. How could an attacker exploit the vulnerability? In a network-based attack, an authenticated attacker with Manage List permissions could execute code remotely on the SharePoint Server.

Affected Products (1)

Microsoft Office

  • Microsoft SharePoint Server Subscription Edition

Security Updates (1)

Acknowledgments

41ae55e9310ff27fa6f26af4727e5590

Revision History

  • 2026-10-13: Information published.