CVE-2021-22681

critical

Description

Rockwell Automation Studio 5000 Logix Designer Versions 21 and later, and RSLogix 5000 Versions 16 through 20 use a key to verify Logix controllers are communicating with Rockwell Automation CompactLogix 1768, 1769, 5370, 5380, 5480: ControlLogix 5550, 5560, 5570, 5580; DriveLogix 5560, 5730, 1794-L34; Compact GuardLogix 5370, 5380; GuardLogix 5570, 5580; SoftLogix 5800. Rockwell Automation Studio 5000 Logix Designer Versions 21 and later and RSLogix 5000: Versions 16 through 20 are vulnerable because an unauthenticated attacker could bypass this verification mechanism and authenticate with Rockwell Automation CompactLogix 1768, 1769, 5370, 5380, 5480: ControlLogix 5550, 5560, 5570, 5580; DriveLogix 5560, 5730, 1794-L34; Compact GuardLogix 5370, 5380; GuardLogix 5570, 5580; SoftLogix 5800.

References

https://us-cert.cisa.gov/ics/advisories/icsa-21-056-03

https://securityaffairs.com/196453/ics-scada/cisa-urges-utilities-to-remove-internet-exposed-plcs-after-minnesota-attacks.html

https://www.securityweek.com/rockwell-automation-patches-vulnerabilities-in-ics-controllers-and-software/

https://claroty.com/blog/advisory-us-critical-infrastructure-actively-targeted-by-iran

https://therecord.media/fbi-pentagon-warn-iran-hacking-groups-target-ot

https://www.securityweek.com/rockwell-vulnerability-allowing-remote-ics-hacking-exploited-in-attacks/

https://thehackernews.com/2026/03/hikvision-and-rockwell-automation-cvss.html

https://securityaffairs.com/189005/security/u-s-cisa-adds-apple-rockwell-and-hikvision-flaws-to-its-known-exploited-vulnerabilities-catalog.html

https://www.cisa.gov/news-events/alerts/2026/03/05/cisa-adds-five-known-exploited-vulnerabilities-catalog

https://www.cisa.gov/news-events/ics-advisories/icsa-24-284-20

https://www.rockwellautomation.com/en-us/trust-center/security-advisories/advisory.SD1672.html

https://www.tenable.com/blog/coordinated-cyberattack-on-minnesota-water-utilities-what-you-need-to-know

https://www.tenable.com/blog/what-to-know-about-cyberav3ngers-the-irgc-linked-group-targeting-critical-infrastructure

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22681

Details

Source: Mitre, NVD

Published: 2021-03-03

Updated: 2026-06-17

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

EPSS

EPSS: 0.50712

Vulnerability Watch

Tenable Research has classified this CVE under the following Vulnerability Watch classification, which includes active and historical (inactive) classifications. You can learn more about these classifications on our blog.

Vulnerability of Interest

Detections

Analytics