Is CVE-2021-22681 in the CISA KEV catalog?

Yes. CVE-2021-22681 is on the CISA Known Exploited Vulnerabilities list, added 2026-03-05.

What is the CVSS severity of CVE-2021-22681?

CVE-2021-22681 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2021-22681?

CVE-2021-22681 has an EPSS score of 25.45% (98th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2021-22681?

No published fix for CVE-2021-22681 has been found yet. It is on the CISA Known Exploited Vulnerabilities list; federal agencies must remediate by 2026-03-26. Apply the vendor's mitigations per CISA's guidance.

CVE & CISA-KEV Catalog

CVE-2021-22681

CRITICALCISA KEVEPSS 98th pctl

9.8

CVSS v3

NVD

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.

CWE-522

How to fix

Actively exploited, no published fix found yet

Federal remediation due: 2026-03-26

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

25.45%probability of exploitation in 30 days

98thpercentile

Very high risk: more likely to be exploited than 98% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Remediation due: 2026-03-26

References

Third-Party Advisory1

us-cert.cisa.gov

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-522 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-17662	Critical	9.8	97%	-	-
CVE-2020-29583	Critical	9.8	90%	KEV	-
CVE-2021-30116	Critical	10.0	86%	KEV + Ransom	Fix
CVE-2024-44000	Critical	9.8	83%	-	Fix
CVE-2018-9160	Critical	9.8	77%	-	-
CVE-2017-9248	Critical	9.8	75%	KEV	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-06.