What’s Vulnerable › Vulnerabilities

CVE-2023-0027: Rockwell Automation Modbus TCP AOI Server Could Leak Sensitive Information

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-03-17 · updated 2026-06-17
• Weakness: CWE-200

Description

Rockwell Automation Modbus TCP Server AOI prior to 2.04.00 is vulnerable to an unauthorized user sending a malformed message that could cause the controller to respond with a copy of the most recent response to the last valid request. If exploited, an unauthorized user could read the connected device’s Modbus TCP Server AOI information.

Affected products

• Rockwell Automation Modbus TCP Server Add On Instructions: from 2.00.00 before 2.04.00 — fixed in 2.04.00

How to fix

Upgrade to a fixed version: Rockwell Automation Modbus TCP Server Add On Instructions 2.04.00. Check the vendor advisory for mitigations.

References

• https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1138766
• https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1138766

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