KEV Intelligence

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-22681

Studio 5000 Logix Designer

Rockwell Automation / Studio 5000 Logix Designer · RSLogix 5000 Versions 16 through 20

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Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
61.0%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-22681 is an unauthenticated vulnerability affecting Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000. Rockwell Automation Studio 5000 Logix Designer Versions 21 and later, and RSLogix 5000...

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Rockwell Automation / Studio 5000 Logix Designer rslogix 5000 versions 16 through 20.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Studio 5000 Logix Designer

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.

Vendor Product Affected Status
n/a Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers RSLogix 5000 Versions 16 through 20 Affected
n/a Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers Studio 5000 Logix Designer: Versions 21 and later Affected
n/a Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers CompactLogix 1768, 1769, 5370, 5380, 5480 Affected
n/a Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers ControlLogix 5550, 5560, 5570, 5580 Affected
n/a Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers DriveLogix 5560, 5730, 1794-L34 Affected
n/a Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers Compact GuardLogix 5370, 5380 Affected
n/a Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers GuardLogix 5570, 5580 Affected
n/a Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers SoftLogix 5800 Affected
Published
03 Mar 2021
Exploitation Reported
01 Jun 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

cisa

CVE References

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CVE

Recorded 01 Jun 2026

Independent exploitation attestation added to the KEV Intelligence record.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source Added
CVE First 2026-06-01 11:38 UTC
CISA 2026-06-02 14:02 UTC
Tenable Blog 2026-07-29 03:19 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
0
User-Agents
0

Raw values available in Pro and Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

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

EPSS

61.0%

Weaknesses

Insufficiently Protected Credentials CWE-522

Recent mention · Tenable Blog

Coordinated “cyberattack” on Minnesota water utilities: What you need to know

A coordinated cyber attack disrupted water systems across more than 30 Minnesota communities. Here is what defenders need to know about the attack so far. This FAQ also details recent cyberactivity targeting internet-exposed PLCs, and how to protect exposed infrastructure.Key...

Read full advisory

All CVSS Scores

CVSS v3.1 9.8 Critical

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

CVSS v2.0 7.5 High

AV:N/AC:L/Au:N/C:P/I:P/A:P

Timeline

From disclosure to observed exploitation

  1. KEV confirmed by Tenable Blog

    Exploitation attested by an external source

  2. Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  3. Added to KEV Intelligence KEV Feed

    High-confidence, third-party attested exploitation

  4. CVE published

    Vulnerability disclosed publicly

  5. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-22681

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-22681",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.60993,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

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