CVE-2026-20951: Microsoft SharePoint Server Remote Code Execution Vulnerability

Overview

Severity
High (CVSS 7.8)
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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-Jan
Released
2026-01-13
EPSS Score
0.07% (percentile: 20.5%)

Description

Improper input validation in Microsoft Office SharePoint allows an unauthorized attacker to execute code locally.

FAQ

According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution? The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. This means an attacker or victim needs to execute code from the local machine to exploit the vulnerability. According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do? The user must open or load attacker‑controlled content—such as importing a malicious WSDL or opening a file—so the application processes it and triggers the vulnerability.

Affected Products (3)

Microsoft Office

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

Security Updates (3)

Acknowledgments

<a href="https://twitter.com/chudypb">Piotr Bazydło (@chudypb)</a>

Revision History

  • 2026-01-13: Information published.