CVE-2020-6998Network attack vector

Communication denial of service via CIP infinite loop

Published Jul 27, 2022 · Updated Apr 17, 2025

Denial of service in Rockwell Automation Logix controllers 33 and earlier allows remote attackers to interrupt CIP communications. The connection-establishment algorithm fails to terminate its control flow when processing specially crafted CIP packet requests, entering an infinite loop. Network access to EtherNet/IP TCP or UDP ports 2222 or 44818 is sufficient, and the resulting hang blocks communications with other products.

CVSS severity5.8
Medium
EPSS probability2.16%
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 Rockwell Automation Logix controllers 33 and earlier allows remote attackers to interrupt CIP communications. The connection-establishment algorithm fails to terminate its control flow when processing specially crafted CIP packet requests, entering an infinite loop. Network access to EtherNet/IP TCP or UDP ports 2222 or 44818 is sufficient, and the resulting hang blocks communications with other products.

The record

CVE
CVE-2020-6998
Published
Jul 27, 2022
Updated
Apr 17, 2025
Vendor
Rockwell Automation
Product
ControlLogix 5570 Controllers
Classifications
CWE-20, T0814
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 27, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=unspecified <=versions 33 and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Rockwell Automation · ControlLogix 5570 Controllersversion=unspecified <=versions 33 and prior
Rockwell Automation · Compact GuardLogix 5370 Controllersversion=unspecified <=versions 33 and prior
Rockwell Automation · Armor GuardLogix Safety Controllersversion=unspecified <=versions 33 and prior
Rockwell Automation · CompactLogix 5370 L2 Controllersversion=unspecified <=versions 33 and prior
Rockwell Automation · Armor Compact GuardLogix 5370 Controllersversion=unspecified <=versions 33 and prior
Rockwell Automation · CompactLogix 5370 L1 Controllersversion=unspecified <=versions 33 and prior
Rockwell Automation · CompactLogix 5370 L3 Controllersversion=unspecified <=versions 33 and prior

Published CVSS scores

8.6NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
5.8ICS-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

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-20Improper Input Validation
T0814Denial of Service

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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