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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| 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.
GitHub 1 repository
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fevar54/Blackash-CVE-2025-20343 ★ 0 · Nov 8, 2025
PoC y analisis de CVE-2025-20343: DoS remoto no autenticado en Cisco ISE via paquetes RADIUS.
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- NCSC-2025-0354 Kwetsbaarheid verholpen in Cisco Identity Services Engine NCSC-NL (Netherlands) · Nov 6, 2025
- WID-SEC-2025-2492 Cisco Identity Services Engine (ISE): Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Nov 5, 2025