Microsoft Exchange: Mehrere Schwachstellen
WID-SEC-2026-2326 · first 15.07.2026 · updated 15.07.2026 · CVSS 9,6
What it is about
Exchange ist ein Groupware und Nachrichtensystem der Firma Microsoft. Ein Angreifer kann mehrere Schwachstellen in Microsoft Exchange ausnutzen, um beliebigen Programmcode auszuführen, erweiterte Berechtigungen zu erlangen oder Spoofing-Angriffe durchzuführen.
Under what conditions?
The BSI does not name any particular preconditions. Exploitable remotely according to the BSI.
What can happen in the worst case
An attacker could use the vulnerability to
- beliebigen Programmcode auszuführen
- erweiterte Berechtigungen zu erlangen oder Spoofing-Angriffe durchzuführen
Am I affected?
Affected according to the BSI:
- Microsoft Exchange Server 2016 Cumulative Update 23
- Microsoft Exchange Server 2019 Cumulative Update 14
- Microsoft Exchange Server Subscription Edition RTM
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 Security Advisory CVE-2026-54998 msrc.microsoft.com
- Microsoft Security Advisory CVE-2026-55009 msrc.microsoft.com
- Microsoft Security Advisory CVE-2026-55008 msrc.microsoft.com
- Microsoft Security Advisory CVE-2026-55006 msrc.microsoft.com
- Microsoft Security Advisory CVE-2026-55005 msrc.microsoft.com
CVE: CVE-2026-55005, CVE-2026-55006, CVE-2026-55008, CVE-2026-55009
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.