CVE-2026-66364

Subscriber crash via nested-length boundary over-read

Published Jul 30, 2026 · Updated Jul 30, 2026

Out-of-bounds read in MZ Automation libIEC61850 before 1.6.2 allows attackers to crash a GOOSE subscriber via a multicast frame. The GOOSE payload parser accepts an attacker-controlled inner element length that exceeds its enclosing length and reads one byte past the boundary. A single unauthenticated Layer 2 multicast frame on the process bus terminates the subscriber process, interrupting service.

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 libIEC61850 before 1.6.2 allows attackers to crash a GOOSE subscriber via a multicast frame. The GOOSE payload parser accepts an attacker-controlled inner element length that exceeds its enclosing length and reads one byte past the boundary. A single unauthenticated Layer 2 multicast frame on the process bus terminates the subscriber process, interrupting service.

The record

CVE
CVE-2026-66364
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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