Executive brief
MZ Automation lib60870 is a software library used in industrial control systems to communicate using the IEC 60870-5-104 protocol, commonly found in energy and water utility networks. A vulnerability in how the library processes specific network messages could allow an attacker to crash the system or potentially read sensitive information from memory. This could lead to service disruptions in critical infrastructure operations if the affected devices become unresponsive.
Technical details
An out-of-bounds read (CWE-125) exists in the TestCommand_getFromBuffer function within cs101_information_objects.c of lib60870-C v2.4.0. The vulnerability is caused by a structural omission where InformationObject_ParseObjectAddress is called without a message size parameter, preventing proper bounds checking. When a crafted IEC 60870-5-104 I-frame with TypeID 104 (C_TS_NA_1) and an inflated object count is processed, the parser reads one byte past the end of the heap-allocated message buffer. This can be triggered remotely over TCP port 2404 without authentication. The issue is addressed in version 2.4.1.
Affected products
- MZ Automation lib60870 2.4.0
Timeline
- 2026-07-15: advisory: Vendor advisory GHSA-g3w7-x5rx-83xm published
- 2026-07-30: disclosed: CISA Advisory ICSA-26-211-11 published
- 2026-07-30: patched: Version 2.4.1 released to address the issue