Microsoft Exchange Online: Schwachstelle ermöglicht Privilegieneskalation
WID-SEC-2026-2191 · first 03.07.2026 · updated 03.07.2026 · CVSS 8,8
What it is about
Exchange ist ein Groupware und Nachrichtensystem der Firma Microsoft. Ein entfernter, authentisierter Angreifer kann eine Schwachstelle in Microsoft Exchange Online ausnutzen, um seine Privilegien zu erhöhen.
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
- seine Privilegien zu erhöhen
Am I affected?
Affected according to the BSI:
- Microsoft Exchange Online
The installed version is usually shown under “Help → About” or in the device’s admin interface.
What helps?
Install the updates provided by the vendor; details in the sources below.
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.
Information and sources
- Original BSI advisory (WID)
- Microsoft Leitfaden für Sicherheitsupdates msrc.microsoft.com
- Microsoft Leitfaden für Sicherheitsupdates vom 2026-07-02 msrc.microsoft.com
CVE: CVE-2026-54998
Source: BSI warning and information service (CERT-Bund); CISA. The assessment of the conditions is my reading of the BSI text; the external pages are in their original language.