CVE-2026-20959: Microsoft SharePoint Server Spoofing Vulnerability
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.
Other sources
Microsoft SharePoint Server Spoofing Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.19127.20442Patch KB5002822 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.10417.20083Patch KB5002825 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.5535.1001Patch KB5002828
Event History
Frequently Asked Questions
What is the severity of CVE-2026-20959?
CVE-2026-20959 is classified as a medium severity vulnerability affecting Microsoft SharePoint Server.
How do I fix CVE-2026-20959?
To fix CVE-2026-20959, apply the latest security patches provided by Microsoft for the affected SharePoint Server versions.
What are the affected products for CVE-2026-20959?
CVE-2026-20959 affects Microsoft SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016.
Who can exploit CVE-2026-20959?
An authorized attacker with network access can exploit CVE-2026-20959 to perform spoofing attacks.
What type of vulnerability is CVE-2026-20959?
CVE-2026-20959 is a spoofing vulnerability that arises from improper neutralization of input during web page generation.