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Microsoft Security Update Guide · SharePoint

Microsoft SharePoint Server Tampering Vulnerability

Microsoft · EN CVE-2026-63512 Important Action required CVSS 6.5

Published

SummaryDetailedSecurity

What does this mean?

  • Tampering. An attacker can change data or settings without permission.
  • 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 6.5 out of 10: medium. 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: KB5002893 16.0.19725.20522
    • Microsoft SharePoint Server 2019: KB5002894 16.0.10417.20198
    • Microsoft SharePoint Server 2019: KB5002896 16.0.10417.20198
    • Microsoft SharePoint Enterprise Server 2016: KB5002905 16.0.5565.1001
    • Microsoft SharePoint Enterprise Server 2016: KB5002906 16.0.5565.1001
  • This applies to SharePoint Server you run yourself. Microsoft updates SharePoint Online in Microsoft 365.

Microsoft Office SharePoint · Tampering

Incorrect authorization in Microsoft Office SharePoint allows an authorized attacker to perform tampering over a network.

SharePoint Office / Microsoft 365 Apps

How do I check if I am affected?

SharePoint Server: check and update

  1. 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.
  2. 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.
  3. 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
  4. You do not need to update SharePoint Online in Microsoft 365; Microsoft does that.

What kind of flaw is this?

Key facts

Released
11 aug 2026
Impact
Tampering
Max severity
Important
Weakness
CWE-863: Incorrect Authorization
CVSS 3.1
6.5 / 5.7 (base / temporal)
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C
Publicly disclosed
No
Exploited
No
Exploitability assessment
Exploitation Less Likely
Customer action required
Yes
Links
Microsoft Security Update Guide · CVE.org

CVSS metrics

Base score metrics
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityHigh
AvailabilityNone
Temporal score metrics
Exploit Code MaturityUnproven
Remediation LevelOfficial Fix
Report ConfidenceConfirmed

Affected products and updates

ProductUpdateBuild
Microsoft SharePoint Server Subscription EditionKB5002893 · Security Update16.0.19725.20522
Microsoft SharePoint Server 2019KB5002894 · Security Update16.0.10417.20198
Microsoft SharePoint Server 2019KB5002896 · Security Update16.0.10417.20198
Microsoft SharePoint Enterprise Server 2016KB5002905 · Security Update16.0.5565.1001
Microsoft SharePoint Enterprise Server 2016KB5002906 · Security Update16.0.5565.1001

FAQ

What could an attacker achieve by exploiting this vulnerability?
An attacker could exploit this vulnerability to make unauthorized modifications to protected system data. This could allow the attacker to alter system state or configuration beyond their normal privileges.
There are multiple update packages available for some of the affected software. Do I need to install all the updates listed in the Security Updates table for the software?
Yes. Customers should apply all updates offered for the software installed on their systems. If multiple updates apply, they can be installed in any order.
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.

Revisions

VersionDateNote
111 aug 2026Information published.

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