Cisco ISE RADIUS DoS via Crafted Requests
CVE-2026-20352 Published on September 16, 2026
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.
Vulnerability Analysis
CVE-2026-20352 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Buffer Overflow Vulnerability?
The software performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.
CVE-2026-20352 has been classified to as a Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2026-20352
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Affected Versions
Cisco Identity Services Engine Software:- Version 3.2.0 is affected.
- Version 3.2.0 p1 is affected.
- Version 3.2.0 p2 is affected.
- Version 3.3.0 is affected.
- Version 3.2.0 p3 is affected.
- Version 3.2.0 p4 is affected.
- Version 3.2.0 p5 is affected.
- Version 3.2.0 p6 is affected.
- Version 3.3 Patch 2 is affected.
- Version 3.3 Patch 1 is affected.
- Version 3.3 Patch 3 is affected.
- Version 3.4.0 is affected.
- Version 3.2.0 p7 is affected.
- Version 3.3 Patch 4 is affected.
- Version 3.4 Patch 1 is affected.
- Version 3.3 Patch 5 is affected.
- Version 3.3 Patch 6 is affected.
- Version 3.4 Patch 2 is affected.
- Version 3.3 Patch 7 is affected.
- Version 3.4 Patch 3 is affected.
- Version 3.5.0 is affected.
- Version 3.4 Patch 4 is affected.
- Version 3.3 Patch 8 is affected.
- Version 3.2 Patch 8 is affected.
- Version 3.5 Patch 1 is affected.
- Version 3.3 Patch 9 is affected.
- Version 3.2 Patch 9 is affected.
- Version 3.4 Patch 5 is affected.
- Version 3.5 Patch 3 is affected.
- Version 3.5 Patch 2 is affected.
- Version 3.3 Patch 10 is affected.
- Version 3.3 Patch 11 is affected.
- Version 3.4 Patch 6 is affected.
- Version 3.2 Patch 10 is affected.