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VulnerabilityCVE-2026-66364Published 2026-07-30

CVE-2026-66364 — MZ Automation GmbH libiec61850

medium

As of 2026-07-31, CVE-2026-66364 is a MEDIUM-severity vulnerability in MZ Automation GmbH libiec61850, CVSS v3.1 6.5, EPSS 0.1% (7.1th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-66364 as of 2026-07-31; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

CVSS v3.1
6.5/10Medium
EPSS
0.1%Higher than 7.1% of scored CVEs
CISA KEV
NoNot in the KEV catalog
Tracked threats
0None linked yet
Priority
3.5/10Threadlinqs triage score
Published
Updated 2026-07-31
CVSS v3.1 6.5 (MEDIUM) · CVSS v4.0 7.1 · EPSS 0.1% (higher than 7.1% of all scored CVEs) · Priority 3.5/10 · Published 2026-07-30

Last updated:

What is CVE-2026-66364?

The GOOSE payload parser contains a boundary handling flaw that can be triggered by a single unauthenticated Layer 2 multicast frame on the process bus. When processing specific payload fields, an attacker controlled inner element length may exceed its enclosing length, causing the parser to over read by one byte. This out-of-bounds read reliably terminates the subscriber process, resulting in a denial-of-service condition.

The record classifies CVE-2026-66364 under weakness class CWE-125. Its CVSS v3 base vector states that the flaw is reachable from an adjacent network, needs no prior authentication, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 67 days ago.

Severity and exploitation probability

CVSS v3.1 base score
6.5 — MEDIUM
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0 base score
7.1
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
EPSS (FIRST)
0.1% probability of exploitation in the next 30 days, higher than 7.1% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
3.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-07-30, last modified 2026-07-31

Is CVE-2026-66364 being exploited?

It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-66364

No vendor patch reference has been recorded for CVE-2026-66364 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-66364

No threat campaign in the Threadlinqs corpus currently references CVE-2026-66364, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.

Other references