Vulnerability · Published Oct 16, 2026 · Assigned by GitHub_M

CVE-2026-48741libIEC61850: Remote NULL dereference in MMS Read alternate-access sub-array path leads to server-side DoS

High 7.5

In plain English

A high-severity null pointer dereference in libiec61850 from mz-automation. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.5%top 55.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
mz-automation	libiec61850	< 1.6.2

Weakness: CWE-129, CWE-252, CWE-476, CWE-754 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/mz-automation/libiec61850/security/advisories/GHSA-8mfr-hq64-9w33 x_refsource_CONFIRM
https://github.com/mz-automation/libiec61850/commit/7c15310405def00cac628ebde4ce1404bfb8a411 x_refsource_MISC
https://github.com/mz-automation/libiec61850/releases/tag/v1.6.2 x_refsource_MISC