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Microsoft Security Update Guide · SharePoint

Microsoft Office SharePoint Elevation of Privilege Vulnerability

Microsoft · EN CVE-2026-88200 Important Action required CVSS 8.8

Published 13 okt 2026

What does this mean?

Elevation of Privilege. An attacker can gain more rights than they should have, for example admin rights.
It can be exploited over the network (including from the internet if the service is reachable there), with an ordinary user account and without any user action.
CVSS 8.8 out of 10: high. Microsoft rates it Important.
No attacks reported; Microsoft expects exploitation to be less likely.
What should you do? Install the security update for the version you run (or a later cumulative update):
- Microsoft SharePoint Server Subscription Edition: KB5002927 16.0.20326.20190
This applies to SharePoint Server you run yourself. Microsoft updates SharePoint Online in Microsoft 365.

Microsoft Office SharePoint · Elevation of Privilege

Privilege context switching error in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.

SharePoint Office / Microsoft 365 Apps

How do I check if I am affected?

SharePoint Server: check and update

Check your farm build in the SharePoint Management Shell:
```
(Get-SPFarm).BuildVersion
```
Or in Central Administration → Upgrade and Migration → Check product and patch installation status.
If the build is equal to or higher than the build under "Affected products and updates" below, this vulnerability is fixed. A later cumulative update includes the fix too.

Otherwise install the update on every server in the farm, then run the SharePoint Products Configuration Wizard, or:

PSConfig.exe -cmd upgrade -inplace b2b -wait -cmd applicationcontent -install -cmd installfeatures -cmd secureresources -cmd services -install

You do not need to update SharePoint Online in Microsoft 365; Microsoft does that.

Key facts

Released

13 okt 2026

Impact

Elevation of Privilege

Max severity

Important

Weakness

CWE-270: Privilege Context Switching Error

CVSS 3.1

8.8 / 7.7 (base / temporal)

Vector string

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Publicly disclosed

Exploited

Exploitability assessment

Exploitation Less Likely

Customer action required

Yes

Links

Microsoft Security Update Guide · CVE.org

CVSS metrics

Base score metrics
Attack Vector	Network
Attack Complexity	Low
Privileges Required	Low
User Interaction	None
Scope	Unchanged
Confidentiality	High
Integrity	High
Availability	High
Temporal score metrics
Exploit Code Maturity	Unproven
Remediation Level	Official Fix
Report Confidence	Confirmed

Affected products and updates

Product	Update	Build
Microsoft SharePoint Server Subscription Edition	KB5002927 · Security Update	`16.0.20326.20190`

FAQ

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.

Revisions

Version	Date	Note
1	13 okt 2026	Information published.

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Source: Microsoft Security Update Guide. 365Fanatic is not affiliated with Microsoft.