CVE-2025-20343

Cisco Identity Services Engine Radius Suppression Denial of Service Vulnerability

Published Nov 5, 2025 CVSS 3.1 · 8.6 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Cisco identity Services Engine
CPEs cpe:2.3:a:cisco:identity_services_engine:3.4.0:-:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch1:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch2:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch3:*:*:*:*:*:*
Vendors & Products Cisco identity Services Engine
Type Values Removed Values Added
First Time appeared Cisco
Cisco identity Services Engine Software
Vendors & Products Cisco
Cisco identity Services Engine Software
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title Cisco Identity Services Engine Radius Suppression Denial of Service Vulnerability
Weaknesses CWE-697
References
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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
cisco
Published
Updated
Nov 5, 2025, 8:07 PM
Reserved
Oct 10, 2024, 7:15 PM
Status
Analyzed
Published
Nov 5, 2025, 5:15 PM
Modified
Oct 18, 2026, 9:10 PM