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High · 8.6 Public exploit CVE-2025-20343 EUVD-2025-37893GHSA-cfwq-p5hw-9v6p

Cisco Identity Services Engine Radius Suppression Denial of Service Vulnerability

Published Nov 5, 2025 · Updated Nov 5, 2025 · Assigned by cisco

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.

Affected products

VendorProductAffectedFixed
Cisco Cisco Identity Services Engine Software 3.4.0, 3.4 Patch 1, 3.4 Patch 2, 3.4 Patch 3 —

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 1 repository

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

Advisories 2

References