Cisco AsyncOS für Secure Email Gateway: Schwachstelle ermöglicht Ausführen von beliebigem Programmcode mit Administratorrechten
WID-SEC-2025-2870 · first 18.12.2025 · updated 16.01.2026 · CVSS 10,0
What it is about
Cisco AsyncOS ist ein Betriebssystem für Cisco Appliances. Das Cisco Secure Email Gateway ist eine Sicherheitslösung zum Schutz der E-Mail Kommunikation. Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Cisco AsyncOS und Cisco Secure Email Gateway ausnutzen, um beliebigen Programmcode mit Administratorrechten auszuführen.
Under what conditions?
Over the network and without logging in. This is the most dangerous combination: attackers can scan reachable devices automatically.
What can happen in the worst case
An attacker could use the vulnerability to
- beliebigen Programmcode mit Administratorrechten auszuführen
Am I affected?
Affected according to the BSI:
- Cisco AsyncOS
- Cisco Secure Email Gateway
- Cisco AsyncOS <15.0.5-016
- Cisco AsyncOS <15.5.4-012
- Cisco AsyncOS <16.0.4-016
The installed version is usually shown under “Help → About” or in the device’s admin interface.
What helps?
Update to at least:
- Cisco AsyncOS 15.0.5-016
- Cisco AsyncOS 15.5.4-012
- Cisco AsyncOS 16.0.4-016
Is the vulnerability already being exploited?
- CVE-2025-20393: exploited in the wild according to CISA, in the catalogue since 17.12.2025.
Information and sources
- Original BSI advisory (WID)
- Cisco Security Advisory cisco-sa-sma-attack-N9bf4 vom 2025-12-17 sec.cloudapps.cisco.com
- Cisco Talos Blog vom 2025-12-17 blog.talosintelligence.com
CVE: CVE-2025-20393
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.