Identity Services Engine
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.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Cisco Identity Services Engine Software 3.2 | See the advisory |
| Cisco Identity Services Engine Software 3.2 | See the advisory |
| Cisco Identity Services Engine Software 3.2 | See the advisory |
| Cisco Identity Services Engine Software 3.3 | See the advisory |
| Cisco Identity Services Engine Software 3.2 | See the advisory |
| Cisco Identity Services Engine Software 3.2 | See the advisory |
| Cisco Identity Services Engine Software 3.2 | See the advisory |
| Cisco Identity Services Engine Software 3.2 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 2 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 1 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 3 | See the advisory |
| Cisco Identity Services Engine Software 3.4 | See the advisory |
| Cisco Identity Services Engine Software 3.2 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 4 | See the advisory |
| Cisco Identity Services Engine Software 3.4 Patch 1 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 5 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 6 | See the advisory |
| Cisco Identity Services Engine Software 3.4 Patch 2 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 7 | See the advisory |
| Cisco Identity Services Engine Software 3.4 Patch 3 | See the advisory |
| Cisco Identity Services Engine Software 3.5 | See the advisory |
| Cisco Identity Services Engine Software 3.4 Patch 4 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 8 | See the advisory |
| Cisco Identity Services Engine Software 3.2 Patch 8 | See the advisory |
| Cisco Identity Services Engine Software 3.5 Patch 1 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 9 | See the advisory |
| Cisco Identity Services Engine Software 3.2 Patch 9 | See the advisory |
| Cisco Identity Services Engine Software 3.4 Patch 5 | See the advisory |
| Cisco Identity Services Engine Software 3.5 Patch 3 | See the advisory |
| Cisco Identity Services Engine Software 3.5 Patch 2 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 10 | See the advisory |
| Cisco Identity Services Engine Software 3.3 Patch 11 | See the advisory |
| Cisco Identity Services Engine Software 3.4 Patch 6 | See the advisory |
| Cisco Identity Services Engine Software 3.2 Patch 10 | See the advisory |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Exploitation
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 11 Oct 2026.