CVE-2021-22681

CRITICALNVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score elevated to 9.8 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-03-05), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.8EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 64%CVSS: 9.8Exploit: cisa kev · ssvc active · epss top5pct · epss highExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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
9.8
EG Score
9.8(high)
EG Risk
99(Act)
EG Risk 99/100SSVC: Act

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS PROB
64%
EPSS %ILE
99%
KEV
⚠ Exploited

Published

March 3, 2021

Last Modified

March 6, 2026

Advisory Details (2)

Auto-updated Sep 17, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22681
cisa Patch Available

Rockwell Automation Logix Controllers (Update A) | CISA

https://us-cert.cisa.gov/ics/advisories/icsa-21-056-03

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 62× in last 7d / 256× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 944 total refreshes for this CVE.

  1. 2026-09-19 22:16 UTCGHSA enrichment
  2. 2026-09-19 18:36 UTCGHSA enrichment
  3. 2026-09-19 14:56 UTCGHSA enrichment
  4. 2026-09-19 11:16 UTCGHSA enrichment
  5. 2026-09-19 07:37 UTCGHSA enrichment
  6. 2026-09-19 03:56 UTCGHSA enrichment
  7. 2026-09-19 00:16 UTCGHSA enrichment
  8. 2026-09-18 20:37 UTCEG score recompute
  9. 2026-09-18 20:37 UTCGHSA enrichment
  10. 2026-09-18 19:23 UTCEPSS rescore
  11. 2026-09-18 19:20 UTCCISA KEV update
  12. 2026-09-18 16:57 UTCGHSA enrichment
  13. 2026-09-18 14:15 UTCCISA KEV update
  14. 2026-09-18 13:17 UTCGHSA enrichment
  15. 2026-09-18 09:37 UTCGHSA enrichment
  16. 2026-09-18 05:57 UTCGHSA enrichment
  17. 2026-09-18 02:18 UTCGHSA enrichment
  18. 2026-09-17 22:38 UTCEG score recompute
  19. 2026-09-17 22:38 UTCGHSA enrichment
  20. 2026-09-17 19:23 UTCEPSS rescore
  21. 2026-09-17 18:57 UTCGHSA enrichment
  22. 2026-09-17 15:15 UTCGHSA enrichment
  23. 2026-09-17 11:35 UTCGHSA enrichment
  24. 2026-09-17 07:53 UTCGHSA enrichment
  25. 2026-09-17 04:13 UTCGHSA enrichment
Show 75 more
  1. 2026-09-17 00:33 UTCGHSA enrichment
  2. 2026-09-16 20:53 UTCGHSA enrichment
  3. 2026-09-16 17:10 UTCEG score recompute
  4. 2026-09-16 17:10 UTCGHSA enrichment
  5. 2026-09-16 14:10 UTCCISA KEV update
  6. 2026-09-16 14:05 UTCEPSS rescore
  7. 2026-09-16 14:04 UTCEPSS rescore
  8. 2026-09-16 13:29 UTCGHSA enrichment
  9. 2026-09-16 09:44 UTCGHSA enrichment
  10. 2026-09-16 06:05 UTCEG score recompute
  11. 2026-09-16 06:05 UTCGHSA enrichment
  12. 2026-09-16 02:24 UTCGHSA enrichment
  13. 2026-09-15 22:43 UTCGHSA enrichment
  14. 2026-09-15 19:02 UTCGHSA enrichment
  15. 2026-09-15 15:22 UTCGHSA enrichment
  16. 2026-09-15 11:42 UTCGHSA enrichment
  17. 2026-09-15 08:02 UTCGHSA enrichment
  18. 2026-09-15 04:22 UTCEG score recompute
  19. 2026-09-15 04:21 UTCGHSA enrichment
  20. 2026-09-15 03:06 UTCEPSS rescore
  21. 2026-09-15 00:41 UTCGHSA enrichment
  22. 2026-09-14 21:01 UTCGHSA enrichment
  23. 2026-09-14 19:24 UTCCISA KEV update
  24. 2026-09-14 17:17 UTCGHSA enrichment
  25. 2026-09-14 13:37 UTCGHSA enrichment
  26. 2026-09-14 09:57 UTCGHSA enrichment
  27. 2026-09-14 06:14 UTCGHSA enrichment
  28. 2026-09-14 02:35 UTCGHSA enrichment
  29. 2026-09-13 22:55 UTCGHSA enrichment
  30. 2026-09-13 19:16 UTCEG score recompute
  31. 2026-09-13 19:16 UTCGHSA enrichment
  32. 2026-09-13 16:43 UTCEPSS rescore
  33. 2026-09-13 15:36 UTCGHSA enrichment
  34. 2026-09-13 11:53 UTCGHSA enrichment
  35. 2026-09-13 08:13 UTCGHSA enrichment
  36. 2026-09-13 04:34 UTCGHSA enrichment
  37. 2026-09-13 00:54 UTCGHSA enrichment
  38. 2026-09-12 21:14 UTCGHSA enrichment
  39. 2026-09-12 17:34 UTCEG score recompute
  40. 2026-09-12 17:34 UTCGHSA enrichment
  41. 2026-09-12 14:57 UTCEPSS rescore
  42. 2026-09-12 13:55 UTCGHSA enrichment
  43. 2026-09-12 10:15 UTCGHSA enrichment
  44. 2026-09-12 06:34 UTCGHSA enrichment
  45. 2026-09-12 02:55 UTCGHSA enrichment
  46. 2026-09-11 23:15 UTCGHSA enrichment
  47. 2026-09-11 19:35 UTCGHSA enrichment
  48. 2026-09-11 18:49 UTCCISA KEV update
  49. 2026-09-11 15:55 UTCEG score recompute
  50. 2026-09-11 15:55 UTCGHSA enrichment
  51. 2026-09-11 12:15 UTCGHSA enrichment
  52. 2026-09-11 08:35 UTCGHSA enrichment
  53. 2026-09-11 04:55 UTCGHSA enrichment
  54. 2026-09-11 01:15 UTCGHSA enrichment
  55. 2026-09-10 21:35 UTCGHSA enrichment
  56. 2026-09-10 19:28 UTCCISA KEV update
  57. 2026-09-10 17:55 UTCGHSA enrichment
  58. 2026-09-10 14:15 UTCGHSA enrichment
  59. 2026-09-10 10:35 UTCEG score recompute
  60. 2026-09-10 10:35 UTCGHSA enrichment
  61. 2026-09-10 09:29 UTCEPSS rescore
  62. 2026-09-10 06:54 UTCGHSA enrichment
  63. 2026-09-10 03:14 UTCGHSA enrichment
  64. 2026-09-09 23:34 UTCGHSA enrichment
  65. 2026-09-09 19:54 UTCGHSA enrichment
  66. 2026-09-09 19:08 UTCCISA KEV update
  67. 2026-09-09 16:11 UTCGHSA enrichment
  68. 2026-09-09 12:31 UTCGHSA enrichment
  69. 2026-09-09 08:49 UTCGHSA enrichment
  70. 2026-09-09 05:09 UTCGHSA enrichment
  71. 2026-09-09 01:29 UTCGHSA enrichment
  72. 2026-09-08 21:50 UTCGHSA enrichment
  73. 2026-09-08 18:54 UTCCISA KEV update
  74. 2026-09-08 18:10 UTCGHSA enrichment
  75. 2026-09-08 14:30 UTCGHSA enrichment

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Frequently asked(6)

What is CVE-2021-22681?
CVE-2021-22681 is a critical vulnerability published on March 3, 2021. 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,…
When was CVE-2021-22681 disclosed?
CVE-2021-22681 was first published in the National Vulnerability Database on March 3, 2021, with the most recent update on March 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-22681 actively exploited?
Yes. CISA added CVE-2021-22681 to the Known Exploited Vulnerabilities catalog on March 5, 2026, affecting Rockwell Multiple Products. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-22681?
CVE-2021-22681 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2021-22681?
CVE-2021-22681 affects Rockwell Multiple Products. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-22681?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-22681, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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