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  3. CVE-2026-20963 affecting SharePoint Server

CVE-2026-20963 affecting SharePoint Server

This section contains time sensitive announcements about specific cyber threats, vulnerabilities and scams. Each alert has information you need to be aware of, and what actions to take to mitigate any risk to you or your organisation.

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4:19pm, 24 March 2026

TLP Rating: Clear

CVE-2026-20963 affecting SharePoint Server

A critical vulnerability in Microsoft SharePoint is under active exploitation. 

A deserialization of untrusted data vulnerability could allow an unauthorised attacker to execute code over a network. 

The NCSC encourages organisations in New Zealand that use affected versions of the product to review the vendor advisory and apply the remediation as soon as possible.

What's happening

Systems affected

This vulnerability affects the following products:

  • Microsoft SharePoint Enterprise Server 2016 versions 16.0.0 before 16.0.5535.1001.
  • Microsoft SharePoint Server 2019 versions 16.0.0 before 16.0.10417.20083.
  • Microsoft SharePoint Server Subscription Edition versions 16.0.0 before 16.0.19127.20442.
  • End-of-life versions of SharePoint may also be affected, and these should be upgraded to patched versions.

What to do

Prevention

To prevent exploitation, update affected products to a patched version. If remediation or mitigation action cannot be undertaken immediately, then we recommend isolating SharePoint from the internet.

More information

Read more about this alert on the vendor website:

CVE-2026-20963 - Microsoft SharePoint Remote Code Execution Vulnerability External Link

If you require more information or further support, submit a report on our website: Report an incident

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