CVE-2026-48741 mz-automation CVE debrief

Who should care

Defenders of industrial control systems using IEC 61850 client and server protocols should assess their exposure to this vulnerability, especially those with array data models. This includes operators of systems that rely on libIEC61850 for communication, as well as security teams and vulnerability management teams responsible for ensuring the security and integrity of these systems. Additionally, platform administrators and owners of affected deployments,

Why it matters

CVE-2026-48741 is a high-severity vulnerability in libIEC61850 that can cause a remote crash of servers with array data models. Defenders of industrial control systems using IEC 61850 client and server protocols should assess their exposure and prioritize patching to version 1.6.2 or later.

• Remote crash of servers with array data models
• Potential disruption of industrial control systems
• Need for verification of libIEC61850 version and array data model impact
• Prioritization of patching to version 1.6.2 or later

Technical summary

The libIEC61850 library, used for IEC 61850 client and server protocols, has a vulnerability in versions prior to 1.6.2. The issue arises from improper validation of alternate-access sub-array ranges in the mms_read_service.c file. When the numberOfElements is greater than zero, the alternateArrayAccess does not validate the sub-array range. This leads to a NULL pointer dereference when MmsValue_getElement returns NULL, causing a crash. The vulnerability can be exploited through a remote MMS Read request, affecting servers with data models containing arrays.

Defensive priority

Defenders should prioritize verifying exposure of IEC 61850 client and server protocols, especially in industrial control systems, and assess the impact of array data models on their systems.

Recommended defensive actions

• Verify the version of libIEC61850 is 1.6.2 or later
• Assess the impact of array data models on IEC 61850 client and server protocols
• Implement compensating controls to detect and prevent exploitation
• Review relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed

Evidence notes

The issue is caused by the lack of validation for alternate-access sub-array ranges in the mms_read_service.c file, leading to a NULL pointer dereference. This can be triggered by a remote MMS Read request.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.