CVE-2022-20756Network attack vector

Unauthenticated RADIUS service interruption via session exhaustion

Published Apr 6, 2022 · Updated Nov 6, 2024

Denial of service in Cisco Identity Services Engine allows remote attackers to stop RADIUS processing through authentication requests. The RADIUS feature improperly handles requests that consume the EAP session limit, leaving the Policy Service Node unable to process further RADIUS packets. RADIUS services are enabled by default; successful exploitation causes authentication and authorization timeouts and requires a manual PSN restart.

CVSS severity8.6
High
EPSS probability1.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco Identity Services Engine allows remote attackers to stop RADIUS processing through authentication requests. The RADIUS feature improperly handles requests that consume the EAP session limit, leaving the Policy Service Node unable to process further RADIUS packets. RADIUS services are enabled by default; successful exploitation causes authentication and authorization timeouts and requires a manual PSN restart.

The record

CVE
CVE-2022-20756
Published
Apr 6, 2022
Updated
Nov 6, 2024
Vendor
ClamAV
Product
Cisco Identity Services Engine
Classifications
CWE-399, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 6, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 6, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Identity Services Engineversion=n/a

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.6CiscoCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-399Resource Management Errors
T1499.002Service Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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