The library function MmsMapping_varAccessSpecToObjectReference in MZ Automation libiec61850 contains a heap‑based buffer overflow that can be triggered by manipulating the GetNamedVariableListAttributesResponse.itemId argument. Because this flaw resides in memory allocation, an attacker could overwrite adjacent heap data when the function processes crafted input. The vulnerability is classed as a local, heap‑based buffer overflow (CWE‑119, CWE‑122), which may allow local users to corrupt memory or potentially execute arbitrary code within the process.

Affected versions are all releases of libiec61850 up to and including 1.6.1. The library is used in many industrial control systems that implement the MMS protocol.

The CVSS score of 4.8 indicates moderate severity, and the EPSS score is not available, so there is limited public information on exploitation frequency. The vulnerability requires local privileged access to the process; it is not listed in the CISA KEV catalog. Attackers with sufficient local access could use the overflow to crash the application or potentially execute code, but without an elevated privilege level or remote entry point the impact is constrained to the host on which the vulnerable component runs.