CVE-2026-20352

Cisco Identity Services Engine RADIUS Denial of Service Vulnerability

Published Sep 16, 2026 CVSS 3.1 · 8.6 High EPSS < 1% KEV · Not listed

Description

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 Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco Identity Services Engine Software

unknown

Version	Status	Constraints
`3.2.0`	affected	—
`3.2.0 p1`	affected	—
`3.2.0 p2`	affected	—
`3.3.0`	affected	—
`3.2.0 p3`	affected	—
`3.2.0 p4`	affected	—
`3.2.0 p5`	affected	—
`3.2.0 p6`	affected	—
`3.3 Patch 2`	affected	—
`3.3 Patch 1`	affected	—
`3.3 Patch 3`	affected	—
`3.4.0`	affected	—
`3.2.0 p7`	affected	—
`3.3 Patch 4`	affected	—
`3.4 Patch 1`	affected	—
`3.3 Patch 5`	affected	—
`3.3 Patch 6`	affected	—
`3.4 Patch 2`	affected	—
`3.3 Patch 7`	affected	—
`3.4 Patch 3`	affected	—
`3.5.0`	affected	—
`3.4 Patch 4`	affected	—
`3.3 Patch 8`	affected	—
`3.2 Patch 8`	affected	—
`3.5 Patch 1`	affected	—
`3.3 Patch 9`	affected	—
`3.2 Patch 9`	affected	—
`3.4 Patch 5`	affected	—
`3.5 Patch 3`	affected	—
`3.5 Patch 2`	affected	—
`3.3 Patch 10`	affected	—
`3.3 Patch 11`	affected	—
`3.4 Patch 6`	affected	—
`3.2 Patch 10`	affected	—

No data.

Vendor Product Versions

Cisco

Identity Services Engine Software

Version	Status	Scheme	Platform
`3.2.0`	affected	semver	—
`3.2.0 p1`	affected	generic	—
`3.2.0 p2`	affected	generic	—
`3.3.0`	affected	semver	—
`3.2.0 p3`	affected	generic	—
`3.2.0 p4`	affected	generic	—
`3.2.0 p5`	affected	generic	—
`3.2.0 p6`	affected	generic	—
`3.3 Patch 2`	affected	generic	—
`3.3 Patch 1`	affected	generic	—
`3.3 Patch 3`	affected	generic	—
`3.4.0`	affected	semver	—
`3.2.0 p7`	affected	generic	—
`3.3 Patch 4`	affected	generic	—
`3.4 Patch 1`	affected	generic	—
`3.3 Patch 5`	affected	generic	—
`3.3 Patch 6`	affected	generic	—
`3.4 Patch 2`	affected	generic	—
`3.3 Patch 7`	affected	generic	—
`3.4 Patch 3`	affected	generic	—
`3.5.0`	affected	semver	—
`3.4 Patch 4`	affected	generic	—
`3.3 Patch 8`	affected	generic	—
`3.2 Patch 8`	affected	generic	—
`3.5 Patch 1`	affected	generic	—
`3.3 Patch 9`	affected	generic	—
`3.2 Patch 9`	affected	generic	—
`3.4 Patch 5`	affected	generic	—
`3.5 Patch 3`	affected	generic	—
`3.5 Patch 2`	affected	generic	—
`3.3 Patch 10`	affected	generic	—
`3.3 Patch 11`	affected	generic	—
`3.4 Patch 6`	affected	generic	—
`3.2 Patch 10`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.573% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-RADIUS-dos-wR3hYPMw

History

Sep 19, 2026 11:00 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Cisco Cisco identity Services Engine Software
Vendors & Products		Cisco Cisco identity Services Engine Software

Sep 17, 2026 4:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Sep 16, 2026 8:30 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
Title		Cisco Identity Services Engine RADIUS Denial of Service Vulnerability
Weaknesses		CWE-119
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-RADIUS-dos-wR3hYPMw
Metrics		cvssV3_1 `{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}`