CVE-2026-20222 Denial of service in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
An unauthenticated adjacent attacker can cause a denial of service by sending crafted EIGRP updates, triggering a memory leak and device reload.
- 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-2026-20222?
CVE-2026-20222 is a high-severity denial of service vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability in the EIGRP implementation in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software 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 improper resource management when handling EIGRP update messages. An attacker could exploit this vulnerability by sending crafted EIGRP updates at a high rate to an affected device. A successful exploit could allow the attacker to trigger a memory leak that will eventually cause the affected device to reload unexpectedly.
Weakness: CWE-401
Which versions are affected by CVE-2026-20222?
How do I fix CVE-2026-20222?
No fix has been published for CVE-2026-20222 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-2026-20222 being exploited?
There is no known exploitation of CVE-2026-20222 in the wild and no public exploit code.
Sources
Also known as GHSA-3p99-hh66-cfh4.