CVE•Published 2021-03-25•Modified 2026-06-03•1 article on news•5 live references•NVD data
CVE-2021-22659Rockwellautomation · Micrologix_1400_firmware
Vulnerability data via NVD (ingested)
CVSS v3.1
8.6
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
EPSS percentile
72
Exploit Prediction Scoring System · top 28% of all CVEs
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.
Timeline
Published 2021-03-25
Modified 2026-06-03
External references
Search for exposed instances
Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).
Shodan · vuln tag0 hosts
vuln:CVE-2021-22659Hosts Shodan has explicitly fingerprinted as vulnerable.
Shodan · OS
os:"Micrologix 1400 Firmware"Hosts Shodan identified as running Micrologix 1400 Firmware.
More intel sources (5)
Shodan report
vuln:CVE-2021-22659Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2021-22659Censys host search filtered to this CVE id.
grep.app
CVE-2021-22659Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2021-22659GitHub code search for direct mentions.
Google dork
"CVE-2021-22659" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.
Known PoCs on GitHub
No public proof-of-concept repositories found for CVE-2021-22659 on GitHub.