What is CVE-2021-22681?

CVE-2021-22681 is a critical-severity vulnerability in Rockwellautomation Compact_guardlogix_5370, classified under Insufficiently Protected Credentials. CVSS score: 9.8/10. Published 2021-03-03.

How severe is CVE-2021-22681?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2021-22681 known to be exploited?

Yes. CVE-2021-22681 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-03-05), indicating it is being actively exploited. 1 public proof-of-concept repositories are indexed.

Vulnerability in Rockwellautomation Compact_guardlogix_5370

CVE-2021-22681

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: Contr…

EPSS: 0.255 (97.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

CWE-522 — Insufficiently Protected Credentials

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2026-03-05. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2026-03-26.

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

ics-cert@hq.dhs.gov (US Government Resource, Third Party Advisory, x_refsource_MISC)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2021-22681?: CVE-2021-22681 is a critical-severity vulnerability in Rockwellautomation Compact_guardlogix_5370, classified under Insufficiently Protected Credentials. CVSS score: 9.8/10. Published 2021-03-03.
How severe is CVE-2021-22681?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-22681 known to be exploited?: Yes. CVE-2021-22681 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-03-05), indicating it is being actively exploited. 1 public proof-of-concept repositories are indexed.