Historical catalog analysis: CISA added this entry on March 05, 2026. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.
What the vulnerability is
CVE-2021-22681 is an insufficient protected credentials vulnerability (CWE-522) affecting Rockwell Automation products. Specifically, a key used to verify communication between Logix controllers and Studio 5000 Logix Designer software may be discoverable. If this key is obtained, it could allow an unauthorized application to establish a connection with the affected Logix controllers.
Exposure and applicability
This vulnerability applies to environments utilizing Rockwell Automation Logix controllers and the associated Studio 5000 Logix Designer software. The primary prerequisite for exploitation is that an unauthorized user must have network access to the controller. This makes the risk highest in environments where industrial control networks are not properly segmented from other business networks or where remote access paths to the PLC (Programmable Logic Controller) layer are insufficiently restricted.
Remediation priorities
Based on our analysis, asset owners should prioritize the following actions to reduce exposure:
- Vendor Mitigation Application: The primary priority is to apply mitigations as specified in the vendor’s instructions. This addresses the underlying credential issue identified by Rockwell Automation.
- Network Access Control: Because network access is a prerequisite for exploitation, operators should review and restrict paths to Logix controllers. Limiting communication to authorized engineering workstations can reduce the likelihood of an unauthorized application reaching the controller.
- Inventory Verification: Plant managers and OT security leaders should identify all instances of Studio 5000 Logix Designer and compatible Logix controllers within their environment to ensure no legacy or shadow systems remain unmitigated.
How to validate remediation
Validation should be conducted through a combination of configuration audits and authorized change control processes. We recommend the following:
* Version and Patch Audit: Verify that the mitigations recommended by the vendor have been applied across all identified controllers and software installations.
* Access Path Review: Use network diagrams or firewall rule audits to confirm that only authorized IP addresses and ports can communicate with the Logix controllers, thereby validating that the prerequisite for exploitation (network access) is restricted.
Note: To maintain operational stability, any validation activities should be performed according to site-specific change control procedures and OEM guidance; avoid active scanning of production equipment.
Limits and open questions
While the vulnerability allows for unauthorized application connections, the source does not specify the exact capabilities an attacker would gain once connected (e.g., whether they could modify logic or simply read data). Additionally, while this vulnerability has been added to the CISA Known Exploited Vulnerabilities catalog, it remains unknown if it has been utilized in ransomware campaigns. Users should be aware that applying mitigations may reduce risk but does not eliminate all potential vectors for unauthorized network access.
Source and editorial note
CVE-2021-22681: Rockwell Multiple Products Insufficient Protected Credentials Vulnerability · Source date: March 05, 2026 · Retrieved August 31, 2026.
Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.
Archive date: March 08, 2026. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: September 08, 2026 at 03:56 UTC.
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