HOMEVULNERABILITIESCVE-2021-22659
HIGH

CVE-2021-22659

CWE-120Published: March 25, 2021· Updated: Jun 17, 2026

8.6
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-22659 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 8.6.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityLow
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Affected Vendors & Products

rockwellautomation2 product(s)
micrologix 1400 firmwaremicrologix 1400
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1129877/loc/en_US#__highlight
ADVISORYhttps://us-cert.cisa.gov/ics/advisories/icsa-21-033-01
ADVISORYhttps://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1129877/loc/en_US#__highlight
ADVISORYhttps://us-cert.cisa.gov/ics/advisories/icsa-21-033-01

All References (4)

→
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

Quick Facts

CVE IDCVE-2021-22659
CVSS Score8.6 / 10
SeverityHIGH
WeaknessCWE-120
CISA KEVNo
Affected1 vendor(s)
PublishedMar 25, 2021

Related CVEs (CWE-120)

CVE-2012-10035
10.0
CVE-2023-4260
10.0
CVE-1999-0046
10.0
CVE-2001-0554
10.0
CVE-2001-0191
10.0
CVE-2010-10016
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-22659 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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