CVE-2025-20343
HighCVSS 8.6Exploitation Probability (EPSS)
Elevated risk53th percentile - higher than 53% of all known CVEs
Summary
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 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 send a specific sequence of crafted RADIUS access request messages to cause a denial of service (DoS) condition.
Risk Assessment
An attacker could remotely trigger a restart of Cisco ISE, causing disruption to authentication and authorization services. This could impact network access and systems relying on ISE.
Recommendation
Apply the fixes provided by Cisco for Cisco ISE. Consider temporarily disabling or modifying the RADIUS reject setting for clients with repeated failures if feasible.
Other vulnerabilities in Cisco Identity Services Engine
See all- CVE-2026-76460CriticalActively exploited
A vulnerability in the API of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to bypass authentication. This is due to insufficient authentication control on an API endpoint. An attacker could send a crafted request to gain unauthorized access to the device by bypassing the web-based management interface.
- CVE-2026-20284Critical
A vulnerability in the SXP REST API of Cisco ISE could allow an authenticated, remote attacker to conduct SQL injection attacks. This is due to insufficient validation of user-supplied input in REST API calls. A successful exploit could allow the attacker to view or modify data on the underlying database, and in single-node deployments could cause a DoS condition.
- CVE-2026-20237Critical
Vulnerability in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-PIC) is due to improper input validation issues (CWE-20). It was discovered during an internal security review and addressed in a hardening release.
- CVE-2026-20211Critical
Vulnerability in Cisco ISE allows an authenticated remote attacker with high-privileged admin credentials to execute arbitrary commands on the underlying OS. It is due to insecure deserialization of Java objects. Single-node deployments may experience DoS.
- CVE-2026-20194Critical
Vulnerability in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-PIC) is due to incorrect resource transfer between spheres (CWE-669). It was discovered during an internal security review and addressed in a hardening release.
- CVE-2026-20192Critical
Vulnerability in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-PIC) is due to improper access control issues (CWE-284). It was discovered during an internal security review and addressed in a hardening release.
- CVE-2026-20176Critical
Vulnerability in Cisco ISE allows an authenticated remote attacker with high-privileged admin credentials to execute arbitrary commands on the underlying OS. It is due to insufficient validation of user-supplied input. Single-node deployments may experience DoS.
- CVE-2026-20130Critical
Vulnerability in Cisco Identity Services Engine (ISE) and ISE Passive Identity Connector (ISE-PIC) is due to improper neutralization of special elements (CWE-74). It was discovered during an internal security review and addressed in a hardening release.
- CVE-2026-20186Critical
A vulnerability in Cisco Identity Services Engine (ISE) allows an authenticated remote attacker to execute arbitrary commands on the underlying OS. The attacker needs at least Read Only Admin credentials and sends a crafted HTTP request.
- CVE-2026-20180Critical
A vulnerability in Cisco Identity Services Engine (ISE) allows an authenticated remote attacker to execute arbitrary commands on the underlying OS. The attacker needs at least Read Only Admin credentials and sends a crafted HTTP request.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS