Network disclosure via stale Modbus response data
Published Jul 24, 2025 · Updated Jul 24, 2025
Buffer over-read in ABB AC500 V2 firmware 2.5.2 and earlier allows remote attackers to read prior Modbus telegram fragments. The Modbus TCP server handles an unsupported function code by returning an invalid telegram with stale buffer data appended to the response. Unauthenticated network access to the PLC is sufficient, and the exposure is limited to fragments of Modbus telegrams previously sent by that controller.
Summary
What happened
Buffer over-read in ABB AC500 V2 firmware 2.5.2 and earlier allows remote attackers to read prior Modbus telegram fragments. The Modbus TCP server handles an unsupported function code by returning an invalid telegram with stale buffer data appended to the response. Unauthenticated network access to the PLC is sufficient, and the exposure is limited to fragments of Modbus telegrams previously sent by that controller.
The record
- CVE
- CVE-2025-7745
- Published
- Jul 24, 2025
- Updated
- Jul 24, 2025
- Vendor
- GENEREX SYSTEMS Computervertriebsgesellschaft mbH
- Product
- AC500 V2
- Classifications
- CWE-126
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 24, 2025CVE publishedPublication date reported by the CVE source.
- Jul 24, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <=2.5.2
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
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