Summary
Impact: Remote Code Execution. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
How could an attacker exploit this vulnerability?
In a network-based attack, an unauthenticated attacker could write arbitrary code to inject and execute code remotely on the SharePoint Server.
Security updates
16.0.5535.1001 — https://support.microsoft.com/help/5002828
16.0.10417.20083 — https://support.microsoft.com/help/5002825
16.0.19127.20442 — https://support.microsoft.com/help/5002822
Vulnerabilities 1
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Critical 9.8
Microsoft SharePoint Remote Code Execution Vulnerability
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
KEV Mar 18, 2026
Revision history
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#2
Updated the CVSS score and corrected FAQs. This is an informational change only.
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#1
Information published.
References
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CVE-2026-20963 Microsoft SharePoint Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss