CVE-2022-20756

CVE-2022-20756 is a high-severity vulnerability in Cisco Identity Services Engine with a CVSS 3.x base score of 8.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-399.

Key facts

Description

A vulnerability in the RADIUS feature of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause the affected system to stop processing RADIUS packets. This vulnerability is due to improper handling of certain RADIUS requests. An attacker could exploit this vulnerability by attempting to authenticate to a network or a service where the access server is using Cisco ISE as the RADIUS server. A successful exploit could allow the attacker to cause Cisco ISE to stop processing RADIUS requests, causing authentication/authorization timeouts, which would then result in legitimate requests being denied access. Note: To recover the ability to process RADIUS packets, a manual restart of the affected Policy Service Node (PSN) is required. See the Details section for more information.

Frequently asked questions

What is CVE-2022-20756?
A vulnerability in the RADIUS feature of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause the affected system to stop processing RADIUS packets. This vulnerability is due to improper handling of certain RADIUS requests. An attacker could exploit this vulnerability by attempting to authenticate to a network or a service where the access server is using Cisco ISE as the RADIUS server. A successful exploit could allow the attacker to cause Cisco ISE to stop processing RADIUS requests, causing authentication/authorization timeouts, which would then result in legitimate requests being denied access. Note: To recover the ability to process RADIUS packets, a manual restart of the affected Policy Service Node (PSN) is required. See the Details section for more information.
How severe is CVE-2022-20756?
CVE-2022-20756 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2022-20756 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-20756?
CVE-2022-20756 primarily affects Cisco Identity Services Engine. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2022-20756?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2022-20756 published?
CVE-2022-20756 was published on 2022-04-06 and last updated on 2026-06-17.

References

Affected products (16)

More vulnerabilities in Cisco Identity Services Engine

All CVEs affecting Cisco Identity Services Engine →

Other CWE-399 (Resource Management Errors) vulnerabilities

Browse all CWE-399 (Resource Management Errors) vulnerabilities →