CVE-2025-20343: Cisco Identity Services Engine Radius Suppression Denial of Service Vulnerability

Published Nov 5, 2025
·
Updated

A vulnerability in the RADIUS setting Reject RADIUS requests from clients with repeated failures on Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause Cisco ISE to restart unexpectedly. This vulnerability is due to a logic error when processing a RADIUS access request for a MAC address that is already a rejected endpoint. An attacker could exploit this vulnerability by sending a specific sequence of multiple crafted RADIUS access request messages to Cisco ISE. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when Cisco ISE restarts.

Affected Software

5 affected components
Cisco Identity Services Engine
Cisco Identity Services Engine=3.4.0
Cisco Identity Services Engine=3.4.0-patch1
Cisco Identity Services Engine=3.4.0-patch2
Cisco Identity Services Engine=3.4.0-patch3

Event History

Nov 5, 2025
CVE Published
via MITRE·04:31 PM
Data Sourced
via MITRE·04:31 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·05:15 PM
DescriptionSeverityWeaknessAffected Software
Nov 6, 2025
News Published
via BleepingComputer·01:31 PM
News Published
via BleepingComputer·01:32 PM

Frequently Asked Questions

1

What is the severity of CVE-2025-20343?

CVE-2025-20343 has a high severity rating due to its potential to cause disruption in service.

2

How do I fix CVE-2025-20343?

To mitigate CVE-2025-20343, ensure that your Cisco Identity Services Engine is updated to the latest security patch provided by Cisco.

3

What are the potential impacts of CVE-2025-20343?

The exploitation of CVE-2025-20343 may allow an unauthenticated attacker to cause the Cisco ISE to restart unexpectedly, affecting network security and access.

4

Who is affected by CVE-2025-20343?

Organizations using the Cisco Identity Services Engine are at risk of CVE-2025-20343 if they have not applied the relevant updates.

5

Is CVE-2025-20343 an authenticated or unauthenticated vulnerability?

CVE-2025-20343 is an unauthenticated vulnerability, allowing remote attackers to exploit it without prior authentication.

Contact

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