CVE-2026-50039Public exploitNetwork attack vector

Unauthenticated service crash via unbounded identifier copy

Published Jul 23, 2026 · Updated Jul 23, 2026

Stack-based buffer overflow in MZ Automation libIEC61850 1.0.0 through 1.6.1 allows remote attackers to crash MMS servers via a ReadRequest. MmsValueCache_lookupValue copies a looked-up item identifier into the fixed 65-byte itemIdCopy stack buffer without bounding the copy. Exploitation requires a server model exposing an object identifier longer than 64 bytes; the tested default server requires no application credentials.

CVSS severity8.7
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in MZ Automation libIEC61850 1.0.0 through 1.6.1 allows remote attackers to crash MMS servers via a ReadRequest. MmsValueCache_lookupValue copies a looked-up item identifier into the fixed 65-byte itemIdCopy stack buffer without bounding the copy. Exploitation requires a server model exposing an object identifier longer than 64 bytes; the tested default server requires no application credentials.

The record

CVE
CVE-2026-50039
Published
Jul 23, 2026
Updated
Jul 23, 2026
Vendor
MZ Automation GmbH
Product
libIEC61850
Classifications
CWE-121, T0814
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 23, 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=1.0.0 <=1.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MZ Automation GmbH · libIEC61850version=1.0.0 <=1.6.1

Published CVSS scores

8.7ICS-CERTCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.5ICS-CERTCVSS:3.1/AV:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T0814Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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