Check Point Advisories

Microsoft SharePoint Server Cross-Site Scripting (CVE-2026-20959)

Check Point Reference: CPAI-2026-3406
Date Published: 30 Apr 2026
Severity: Medium
Last Updated: Thursday 30 April, 2026
Source:
Industry Reference:CVE-2026-20959
Protection Provided by:

Security Gateway
R81, R80, R77, R75
Who is Vulnerable? Microsoft SharePoint Server Subscription prior to 16.0.19127.20442
Microsoft SharePoint Server 2016
Microsoft SharePoint Server 2019
Vulnerability Description A cross-site scripting vulnerability in Microsoft SharePoint Server allows an authorized attacker to perform spoofing over a network.

Protection Overview

This protection detects attempts to exploit this vulnerability.

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, click on Protection tab and select the version of your choice.

Security Gateway R81 / R80 / R77 / R75

  1. In the IPS tab, click Protections and find the Microsoft SharePoint Server Cross-Site Scripting (CVE-2026-20959) protection using the Search tool and Edit the protection's settings.
  2. Install policy on all Security Gateways.

This protection's log will contain the following information:

Attack Name:  WordPress Enforcement Protection.
Attack Information:  Microsoft SharePoint Server Cross-Site Scripting (CVE-2026-20959)

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