CVE-2025-20111 Cisco Nexus 3000 and 9000 Series Switches Layer 2 Ethernet Denial of Service Vulnerability
An unauthenticated adjacent attacker can cause a denial of service by sending crafted Ethernet frames to Cisco Nexus switches.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-20111?
CVE-2025-20111 is a high-severity denial of service vulnerability in Cisco NX-OS Software, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability in the health monitoring diagnostics of Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of specific Ethernet frames. An attacker could exploit this vulnerability by sending a sustained rate of crafted Ethernet frames to an affected device. A successful exploit could allow the attacker to cause the device to reload.
Weakness: CWE-1220
Which versions are affected by CVE-2025-20111?
How do I fix CVE-2025-20111?
No fix has been published for CVE-2025-20111 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-20111 being exploited?
There is no known exploitation of CVE-2025-20111 in the wild and no public exploit code.
Sources
Also known as GHSA-q737-5cw3-3g78.