CVE-2022-20726Network attack vector

Unauthenticated service interruption via socket error handling

Published Apr 15, 2022 · Updated Nov 6, 2024

Denial of service in Cisco IOS IOx allows remote attackers to stop the IOx web server from processing requests with sustained TCP traffic. Insufficient error handling for socket operations lets a sustained rate of crafted TCP traffic exhaust the web server's ability to handle requests. The attack requires network reachability to IOx on an affected 809 or 829 Industrial ISR, CGR1000 Compute Module, or IC3000 gateway and interrupts IOx management requests without reported data access or code execution.

CVSS severity5.3
Medium
EPSS probability1.13%
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 IOS IOx allows remote attackers to stop the IOx web server from processing requests with sustained TCP traffic. Insufficient error handling for socket operations lets a sustained rate of crafted TCP traffic exhaust the web server's ability to handle requests. The attack requires network reachability to IOx on an affected 809 or 829 Industrial ISR, CGR1000 Compute Module, or IC3000 gateway and interrupts IOx management requests without reported data access or code execution.

The record

CVE
CVE-2022-20726
Published
Apr 15, 2022
Updated
Nov 6, 2024
Vendor
ClamAV
Product
Cisco IOS
Classifications
CWE-755, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 15, 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 IOSversion=n/a

Published CVSS scores

5.3Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
5.0NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-755Improper Handling of Exceptional Conditions
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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