Description
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.
Published: 2021-03-25
Score: 7.5 High
EPSS: 1.7% Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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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.
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'}


Subscriptions

Rockwellautomation Micrologix 1400 Micrologix 1400 Firmware
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: 2026-06-17T03:37:31.840

Link: CVE-2021-22659

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses