Security readout for executives and security teams
Plain-English summary
This flaw affects Rockwell Automation engineering software and Logix controller communications. An unauthenticated network attacker could bypass a verification mechanism and authenticate to listed controllers. Because CISA lists CVE-2021-22681 in KEV, treat exposed affected systems as urgent operational technology risk.
Executive priority
High priority for OT owners. The combination of critical CVSS, unauthenticated network access, controller impact, and KEV status warrants accelerated inventory, exposure review, and vendor-guided remediation planning.
Technical view
CVE-2021-22681 is a CWE-522 weakness in Studio 5000 Logix Designer versions 21 and later and RSLogix 5000 versions 16 through 20. The vulnerable verification key mechanism can be bypassed remotely without privileges or user interaction, impacting confidentiality, integrity, and availability across listed Logix controller families.
Likely exposure
Exposure is likely where affected RSLogix or Studio 5000 environments communicate with listed CompactLogix, ControlLogix, DriveLogix, GuardLogix, or SoftLogix controllers, especially across reachable engineering or OT network paths.
Exploitation context
CISA KEV listing supports known exploitation. The source bundle does not provide exploit details, affected deployment counts, or a public proof-of-concept status. Avoid assuming broader exploitation mechanics beyond the KEV signal.
Researcher notes
Evidence supports an authentication or verification bypass tied to key-based controller communication verification. The prompt sources do not include patch version details, exploit primitives, or safe detection indicators, so validation should remain inventory- and vendor-advisory driven.
Mitigation direction
- Review the CISA ICS advisory and Rockwell guidance for named remediation.
- Prioritize affected internet- or enterprise-reachable OT paths first.
- Apply only vendor-recommended updates or compensating controls.
- Reduce unnecessary network reachability to affected controller communications.
- Track remediation against the CISA KEV due-date process if applicable.
Validation and detection
- Inventory RSLogix 5000 versions 16 through 20.
- Inventory Studio 5000 Logix Designer versions 21 and later.
- Map communications to listed Logix controller families.
- Confirm whether affected assets are reachable from untrusted networks.
- Verify remediation status against the CISA ICS advisory.
Public sources used
Michael Williams reviewed this cited source version on .
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-522: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-22681 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://us-cert.cisa.gov/ics/advisories/icsa-21-056-03CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22681CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Insufficiently Protected Credentials
Insufficiently Protected Credentials represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.