CVE-2021-22681: Rockwell Multiple Products Insufficient Protected Credentials Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 5 Mar 2026, 1,828 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 63.6%
EPSS score, percentile 99.2 of all scored records
- How severe?
- 9.8 Critical
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline 26 Mar 2026. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- RSLogix 5000 Versions 16 through 20
- Studio 5000 Logix Designer: Versions 21 and later
- CompactLogix 1768, 1769, 5370, 5380, 5480
- ControlLogix 5550, 5560, 5570, 5580
- DriveLogix 5560, 5730, 1794-L34
- Compact GuardLogix 5370, 5380
and 2 more in the table below
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date for this action: 26 March 2026.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://support.rockwellautomation.com/app/answers/answer_view/a_id/1130301/~/cve-2021-22681%3A-authentication-bypass-vulnerability-found-in-logix-controllers-
- https://www.cisa.gov/news-events/ics-advisories/icsa-21-056-03
- https://nvd.nist.gov/vuln/detail/CVE-2021-22681
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | RSLogix 5000 Versions 16 through 20 |
| Affected | Studio 5000 Logix Designer: Versions 21 and later |
| Affected | CompactLogix 1768, 1769, 5370, 5380, 5480 |
| Affected | ControlLogix 5550, 5560, 5570, 5580 |
| Affected | DriveLogix 5560, 5730, 1794-L34 |
| Affected | Compact GuardLogix 5370, 5380 |
| Affected | GuardLogix 5570, 5580 |
| Affected | SoftLogix 5800 |
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
Multiple Rockwell products contain an insufficient protected credentials vulnerability. Studio 5000 Logix Designer software may allow a key to be discovered. This key is used to verify Logix controllers are communicating with Rockwell Automation design software. If successfully exploited, this vulnerability could allow an unauthorized application to connect with Logix controllers. To leverage this vulnerability, an unauthorized user would require network access to the controller.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2021-22681 to its Known Exploited Vulnerabilities (KEV) catalog on 5 Mar 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 26 Mar 2026.
- The CVE record was published on 3 Mar 2021, 1,828 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 63.6% (percentile 99.2), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 3 Mar 2021 | CVE record published |
| 5 Mar 2026 | Added to CISA KEV |
| 6 Mar 2026 | CVE record last updated |
| 26 Mar 2026 | CISA due date for the required action |