CVE-2021-22681
CISA KEVAs of 2026-03-06, CVE-2021-22681 is a CVSS 9.8 (CRITICAL-severity) vulnerability. CISA KEV-listed (known exploited). EPSS exploitation probability 15.4%. Threadlinqs Intelligence tracks 3 threats exploiting it.
Last updated: 2026-03-06
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.
CVSS v3 vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses (CWE)
CWE-522
Exploitation status
CISA KEV-listed (known exploited)
Threats tracking this CVE
- Iran-Linked CyberAv3ngers (BAUXITE) Exploiting Internet-Exposed Rockwell, Schneider Electric, and Siemens PLCs Across US Water, Energy, and Government Infrastructure (CISA AA26-097A) — CRITICAL
- Iranian IRGC CyberAv3ngers APT Campaign Targeting Rockwell/Allen-Bradley PLCs (CISA AA26-097A) — CRITICAL
- CISA KEV: Hikvision Camera Auth Bypass (CVE-2017-7921) & Rockwell Logix Credential Exposure (CVE-2021-22681) — Active Exploitation — CRITICAL
References
- https://us-cert.cisa.gov/ics/advisories/icsa-21-056-03
- https://us-cert.cisa.gov/ics/advisories/icsa-21-056-03
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22681
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Enriched from CVE.org, NVD (this product uses the NVD API but is not endorsed or certified by the NVD), FIRST EPSS, CISA KEV, and GitHub Security Advisories.