CVE-2026-20352: Cisco Identity Services Engine RADIUS Denial of Service Vulnerability
A vulnerability in the RADIUS feature of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of certain RADIUS requests. An attacker could exploit this vulnerability by sending a crafted RADIUS request directly to an affected device. A successful exploit could allow the attacker to cause the ISE node to become unavailable. For single node deployments in that condition, endpoints that have not already authenticated would be unable to access the network until the node comes back up on its own.
Affected Software
Event History
Frequently Asked Questions
What does an attacker need to exploit this issue?
An attacker does not need authentication or user interaction. They need network access to send a crafted RADIUS request directly to an affected ISE device.
What is the operational impact if the affected ISE node becomes unavailable?
The exploit can make the ISE node unavailable. In a single-node deployment, endpoints that have not already authenticated cannot access the network until the node recovers on its own.