CVE-2025-20343

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.

CVSS v3.1

7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1

8.6 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS

0.69% chance of exploitation in the next 30 days, 50th percentile

Published

2025-11-05

Proof-of-concept exploits (1)

• fevar54/Blackash-CVE-2025-20343

References

• CVE Record
• NVD entry

Related

• CVE-2023-21839
• CVE-2023-43654
• CVE-2024-21182
• CVE-2024-3094
• CVE-2024-42461
• CVE-2025-29943