Is CVE-2026-66369 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-66369 being exploited in the wild.

How severe is CVE-2026-66369?

Medium severity, with a CVSS score of 6.5, published 30 July 2026.

Which products and versions are affected?

MZ Automation GmbH libiec61850 < 1.6.2.

Is there a fix for CVE-2026-66369?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-66369 attacked?

It is attacked from the adjacent network, in a software library.

Am I affected by CVE-2026-66369?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-66369: MZ Automation libiec61850 DoS in GOOSE parser

Q: Is there a fix for CVE-2026-66369?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

Q: How is CVE-2026-66369 attacked?

It is attacked from the adjacent network, in a software library.

Q: Am I affected by CVE-2026-66369?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-66369 · Severity: medium · CVSS 6.5 · Published 2026-07-30

A vulnerability exists in a widely used library for industrial power grid communication. An attacker on the local network can send a single malicious message to crash the software responsible for monitoring electrical equipment. This results in a denial-of-service, potentially disrupting the visibility and control of critical energy infrastructure.

Quick answers

Is CVE-2026-66369 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-66369 being exploited in the wild.
How severe is CVE-2026-66369?: Medium severity, with a CVSS score of 6.5, published 30 July 2026.
Which products and versions are affected?: MZ Automation GmbH libiec61850 < 1.6.2.
Is there a fix for CVE-2026-66369?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-66369 attacked?: It is attacked from the adjacent network, in a software library.
Am I affected by CVE-2026-66369?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An off-by-one boundary-handling flaw exists within the GOOSE parser component of libiec61850. The vulnerability is triggered when the parser incorrectly advances its internal buffer position while processing specific fields in a GOOSE message, leading to a heap out-of-bounds read (CWE-125). An unauthenticated attacker on the same Layer-2 network (process bus) can exploit this by sending a single crafted multicast frame. Successful exploitation reliably terminates the subscriber process, resulting in a denial-of-service. The issue is resolved in version 1.6.2.

Affected products

MZ Automation GmbH libiec61850 < 1.6.2

Timeline

2026-07-30: disclosed
2026-07-30: advisory

References

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