Rockwell Automation MicroLogix 1400 Version 21.6 and below may allow a remote unauthenticated attacker to send a specially crafted Modbus packet allowing the attacker to retrieve or modify random values in the register. If successfully exploited, this may lead to a buffer overflow resulting in a denial-of-service condition. The FAULT LED will flash RED and communications may be lost. Recovery from denial-of-service condition requires the fault to be cleared by the user.

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Advisories
Source ID Title
EUVD EUVD EUVD-2021-9795 Rockwell Automation MicroLogix 1400 Version 21.6 and below may allow a remote unauthenticated attacker to send a specially crafted Modbus packet allowing the attacker to retrieve or modify random values in the register. If successfully exploited, this may lead to a buffer overflow resulting in a denial-of-service condition. The FAULT LED will flash RED and communications may be lost. Recovery from denial-of-service condition requires the fault to be cleared by the user.
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 03 Jun 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: icscert

Published:

Updated: 2026-06-03T13:10:07.459Z

Reserved: 2021-01-05T00:00:00.000Z

Link: CVE-2021-22659

cve-icon Vulnrichment

Updated: 2024-08-03T18:51:07.020Z

cve-icon NVD

Status : Modified

Published: 2021-03-25T16:15:14.040

Modified: 2026-06-03T14:16:24.220

Link: CVE-2021-22659

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses