Cisco IOS, Cisco IOS XE und Cisco Secure Firewall Threat Defense: Schwachstelle ermöglicht Denial of Service
WID-SEC-2026-0866 · first 26.03.2026 · updated 26.03.2026 · CVSS 8,6
What it is about
Cisco Internetwork Operating System (IOS) ist ein Betriebssystem, das für Cisco Geräte wie z. B. Router und Switches eingesetzt wird. Cisco Secure Firewall Threat Defense ist eine Sicherheitslösung, die Funktionen wie Firewall, Intrusion Prevention und erweiterten Malware-Schutz in einer einzigen Appliance integriert. Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Cisco IOS, Cisco IOS XE und Cisco Secure Firewall Threat Defense ausnutzen, um einen Denial of Service Angriff durchzuführen.
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
- einen Denial of Service Angriff durchzuführen
Am I affected?
Affected according to the BSI:
- Cisco IOS
- Cisco IOS XE
- Cisco Secure Firewall Threat Defense
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)
- Cisco Security Advisory cisco-sa-asa-ftd-ios-dos-kPEpQGGK vom 2026-03-25 sec.cloudapps.cisco.com
CVE: CVE-2026-20012
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.