Cross-Site Scripting Vulnerability in Microsoft SharePoint by Microsoft
CVE-2026-20959

4.6MEDIUM

Key Information:

Vendor

Microsoft
Status
Microsoft Sharepoint Enterprise Server 2016
Microsoft Sharepoint Server 2019
Microsoft Sharepoint Server Subscription Edition
Vendor
CVE Published:
13 January 2026

What is CVE-2026-20959?

This vulnerability in Microsoft SharePoint arises from improper input neutralization during web page generation, which allows authorized attackers to exploit the system. By executing cross-site scripting attacks, these individuals can spoof content, potentially leading to unauthorized access or data manipulation across the network. Organizations using affected versions should apply the necessary patches to mitigate associated risks.

Affected Version(s)

Microsoft SharePoint Enterprise Server 2016 x64-based Systems 16.0.0 < 16.0.5535.1001

Microsoft SharePoint Server 2019 x64-based Systems 16.0.0 < 16.0.10417.20083

Microsoft SharePoint Server Subscription Edition x64-based Systems 16.0.0 < 16.0.19127.20442

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

EPSS Score

6% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
4.6
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.