CVE-2022-20756
Cisco Identity Services Engine RADIUS Service Denial of Service Vulnerability
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.6
Cisco Identity Services Engine RADIUS Service Denial of Service Vulnerability
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.
- Record
CVE-2022-20756- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-399
- Updated
- 2026-11-02
EUVDEUVD-2022-26006
8.6
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.
- Record
EUVD-2022-26006- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-qwcc-f7fm-5q6x
7.5
A vulnerability in the RADIUS feature of Cisco Identity Services Engine (ISE) could allow an...
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.
- Record
GHSA-qwcc-f7fm-5q6x- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
NVD
8.6
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.
- Record
CVE-2022-20756- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-399
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2022-20756 is a high vulnerability (CVSS 8.6) in Cisco Identity Services Engine, published April 6, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.46%, the 73rd percentile. No source names a fixed version.