{"id":"CVE-2021-22659","aliases":["EUVD-2021-9795","GHSA-fv9f-8rj8-45rf"],"status":"published","title":"Rockwell Automation MicroLogix 1400 Version 21.6 and below may allow a remote unauthenticated...","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.","severity":{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-11","score":0.01795,"percentile":0.78718,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-120"],"published":"2021-03-25T15:59:07Z","modified":"2026-06-17T03:37:31Z","products":[{"vendor":"rockwellautomation","product":"micrologix_1400_firmware"}],"references":[{"url":"https://us-cert.cisa.gov/ics/advisories/icsa-21-033-01","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","US Government Resource"]},{"url":"https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1129877/loc/en_US#__highlight","tags":["x_refsource_MISC","x_transferred","Permissions Required","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-22659"},{"url":"https://github.com/advisories/GHSA-fv9f-8rj8-45rf"}],"sources":{"cve":[{"id":"CVE-2021-22659","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.","status":"published","published":"2021-03-25T15:59:07Z","modified":"2026-06-03T13:10:07.459Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"adp"}],"cwes":["CWE-120"],"updated_at":"2026-11-02T14:32:58.028461Z"}],"euvd":[{"id":"EUVD-2021-9795","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.","status":"published","published":"2021-03-25T15:59:07Z","modified":"2026-06-03T13:10:07Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T18:20:54.727632Z"}],"ghsa":[{"id":"GHSA-fv9f-8rj8-45rf","title":"Rockwell Automation MicroLogix 1400 Version 21.6 and below may allow a remote unauthenticated...","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.","status":"published","published":"2022-05-24T17:45:23Z","modified":"2026-06-03T15:31:36Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high"}],"cwes":["CWE-120"],"updated_at":"2026-11-02T15:08:30.717444Z"}],"nvd":[{"id":"CVE-2021-22659","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.","status":"published","published":"2021-03-25T16:15:14.04Z","modified":"2026-06-17T03:37:31.84Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","level":"high","assessor":"primary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-120"],"updated_at":"2026-11-02T14:06:51.197859Z"}]}}