What it is about

Microsoft Sharepoint Services ist ein Portalsystem für die zentrale Verwaltung von Dokumenten und Anwendungen. Die Inhalte werden u.a. über Webseiten zur Verfügung gestellt. Ein entfernter, authentisierter Angreifer kann eine Schwachstelle in Microsoft SharePoint und Microsoft SharePoint Server ausnutzen, um einen Cross-Site Scripting Angriff durchzuführen.

Under what conditions?

Over the network, but only with valid access (login required), for example with stolen credentials or as an insider.

What can happen in the worst case

An attacker could use the vulnerability to

• einen Cross-Site Scripting Angriff durchzuführen

Am I affected?

Affected according to the BSI:

• Microsoft SharePoint Subscription Edition <16.0.19725.20434
• Microsoft SharePoint Server 2019 <16.0.10417.20175
• Microsoft SharePoint Server 2016 Enterprise <16.0.5561.1001

The installed version is usually shown under “Help → About” or in the device’s admin interface.

What helps?

Update to at least:

• Microsoft SharePoint Subscription Edition 16.0.19725.20434
• Microsoft SharePoint Server 2019 16.0.10417.20175
• Microsoft SharePoint Server 2016 Enterprise 16.0.5561.1001

Is the vulnerability already being exploited?

None of the CVEs is in the CISA catalogue of exploited vulnerabilities. That does not mean there are no attacks, only that none are documented.