CVE-2021-22659

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.

• CWE-120

• https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1129877/loc/en_US#__highlightPermissions Required, Vendor Advisory
• https://us-cert.cisa.gov/ics/advisories/icsa-21-033-01Third Party Advisory, US Government Resource
• https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1129877/loc/en_US#__highlightPermissions Required, Vendor Advisory
• https://us-cert.cisa.gov/ics/advisories/icsa-21-033-01Third Party Advisory, US Government Resource

Published

Mar 25, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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