CVE-2022-20756

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

1.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2022-04-06 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:25 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.5% in the next 30 days (EPSS).
• Severity: 8.6 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2022-04-06 19:15 UTC

Last modified

2026-06-17 04:25 UTC

Exploit probability

1.5% · EPSS, next 30 days

Weakness

CWE-399

Record status

Modified

Affected

• Cisco Identity Services Engine 2.2.0
• Cisco Identity Services Engine 2.4.0
• Cisco Identity Services Engine 2.6.0
• Cisco Identity Services Engine 2.7.0
• Cisco Identity Services Engine 2.7.0.356
• Cisco Identity Services Engine 3.0.0
• Cisco Identity Services Engine 3.1

Attack profile CVSS 3.1 · 8.6

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2022-20756.md and follow it. Check whether this project is affected by CVE-2022-20756. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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