CVE-2026-66369

Subscriber crash via off-by-one GOOSE parsing

Published Jul 30, 2026 · Updated Jul 30, 2026

Out-of-bounds read in MZ Automation GmbH libIEC61850 before 1.6.2 allows remote attackers to crash GOOSE subscribers via multicast. The GOOSE parser advances its internal buffer position incorrectly while processing specific message fields, producing a heap out-of-bounds read. Reachability requires a single unauthenticated Layer-2 multicast frame from the process-bus segment; the bounded consequence is subscriber-process termination and service interruption.

CVSS severity7.1
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in MZ Automation GmbH libIEC61850 before 1.6.2 allows remote attackers to crash GOOSE subscribers via multicast. The GOOSE parser advances its internal buffer position incorrectly while processing specific message fields, producing a heap out-of-bounds read. Reachability requires a single unauthenticated Layer-2 multicast frame from the process-bus segment; the bounded consequence is subscriber-process termination and service interruption.

The record

CVE
CVE-2026-66369
Published
Jul 30, 2026
Updated
Jul 30, 2026
Vendor
MZ Automation GmbH
Product
libIEC61850
Classifications
CWE-125, T0814
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.6.2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

MZ Automation GmbH · libIEC61850version=0 <1.6.2

Published CVSS scores

7.1ICS-CERTCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
6.5ICS-CERTCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T0814Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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