Summary
Impact: Elevation of Privilege. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could overwrite arbitrary file content in the security context of the local system.
Is the Preview Pane an attack vector for this vulnerability?
No, the Preview Pane is not an attack vector.
I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running?
Yes. The same KB number applies to both SharePoint Server 2016 and SharePoint Enterprise Server 2016. Customers running either version should install the security update to be protected from this vulnerability.
How could an attacker exploit this vulnerability?
An authenticated attacker could send a specially crafted request to an affected SharePoint server to perform an operation beyond the permissions granted to their account. Successful exploitation could allow the attacker to modify protected content or administrative configuration. No additional user interaction is required.
Security updates
16.0.20326.20190 — https://support.microsoft.com/help/5002927
Vulnerabilities 1
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High 8.8
Microsoft Office SharePoint Elevation of Privilege Vulnerability
Missing authorization in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.
Revision history
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#1
Information published.
References
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CVE-2026-88198 Microsoft Office SharePoint Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88198
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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