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CVE-2025-20343

HIGHCVSS 7.5/10EPSS 0.67%

Last modified

CVE-2025-20343 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.67% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

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

EPSS Probability
0.67%

47.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
CiscoIdentity Services Engine3.4.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is 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.
How severe is CVE-2025-20343?
CVE-2025-20343 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.67% probability of exploitation in the next 30 days.
How do I fix CVE-2025-20343?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-20343?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST