CVE-2021-22681
Confirmed PUBLISHEDRockwell Automation Studio 5000 Logix Designer Versions 21 and later, and RSLogix 5000 Versions 16 through 20 use a key to verify Logix controllers...
1 day faster than CISA KEV
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
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.
- CVE Published
- Mar 03, 2021
- Exploitation Reported
- Jun 01, 2026
- CVSS
- 9.8 Critical
- EPSS
- 25.5%
Affected Versions
| Vendor | Product | Version | 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 |
CVE References
- us-cert.cisa.gov/ics/advisories/icsa-21-056-03 us-cert.cisa.gov · CVE Record https://us-cert.cisa.gov/ics/advisories/icsa-21-056-03
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CVE First | 2026-06-01 11:38 UTC |
| CISA | 2026-06-02 14:02 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AV:N/AC:L/Au:N/C:P/I:P/A:P
Exploitation Status
Exploited in the wild
Recorded 2026-06-01 11:38:00 UTC · CVE
Weaknesses (CWE)
-
Insufficiently Protected Credentials
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
14:02 UTC about 2 months ago14:02 UTC · about 2 months ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
11:38 UTC about 2 months ago11:38 UTC · about 2 months ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
17:59 UTC over 5 years ago17:59 UTC · over 5 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC over 5 years ago00:00 UTC · over 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-22681
{
"cve_id": "CVE-2021-22681",
"title": "Rockwell Automation Studio 5000 Logix Designer Versions 21 and later, and RSL...",
"affected_vendor": "Rockwell Automation",
"affected_product": "Studio 5000 Logix Designer, RSLogix 5000",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.8,
"epss_score": 0.25455,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}