CVE-2026-48741

libIEC61850: Remote NULL dereference in MMS Read alternate-access sub-array path leads to server-side DoS

State: Published
Severity: 7.5 High
Published: Oct 16, 2026
Updated: Oct 21, 2026
Reserved: May 22, 2026

Description

libIEC61850 is an open-source implementation of IEC 61850 client and server protocols including MMS, GOOSE, Sampled Values, and R-Session. Prior to 1.6.2, alternateArrayAccess in src/mms/iso_mms/server/mms_read_service.c does not validate an alternate-access sub-array range when numberOfElements is greater than zero. An out-of-range MmsValue_getElement call returns NULL, and the sub-array branch passes that value to MmsValue_isDeletable, causing a NULL pointer dereference. A remote MMS Read request can therefore crash servers whose data models contain arrays, while the single-element error path handles the same invalid index safely. This issue is fixed in version 1.6.2.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	GitHub_M

Weaknesses

CWE-129 Improper Validation of Array Index
CWE-252 Unchecked Return Value
CWE-476 NULL Pointer Dereference
CWE-754 Improper Check for Unusual or Exceptional Conditions

Affected Products

Product	Versions
libiec61850mz-automation	< 1.6.2Affected

References

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