Controller outage via malformed CIP Forward Open
Published Jan 20, 2026 · Updated Jan 20, 2026
Improper input validation in Rockwell Automation CompactLogix 5370 firmware allows remote attackers to interrupt service via CIP. The controller fails to validate a quantity in a malformed CIP Forward Open message and enters a major nonrecoverable fault. An unauthenticated attacker on an adjacent network can trigger the fault without user interaction; recovery requires restarting the controller.
Summary
What happened
Improper input validation in Rockwell Automation CompactLogix 5370 firmware allows remote attackers to interrupt service via CIP. The controller fails to validate a quantity in a malformed CIP Forward Open message and enters a major nonrecoverable fault. An unauthenticated attacker on an adjacent network can trigger the fault without user interaction; recovery requires restarting the controller.
The record
- CVE
- CVE-2025-11743
- Published
- Jan 20, 2026
- Updated
- Jan 20, 2026
- Vendor
- Rockwell Automation
- Product
- CompactLogix 5370
- Classifications
- CWE-1284, T0814
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 20, 2026CVE publishedPublication date reported by the CVE source.
- Jan 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=Version 34.013 and prior, Version 35.012 and prior, Version 36.011
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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