CVE-2026-63550Network attack vector

MMS process crash via incorrect BER position advance

Published Jul 30, 2026 · Updated Jul 30, 2026

Out-of-bounds read in libIEC61850 before 1.6.2 allows remote authenticated users to crash the MMS handling process over TCP port 102. The MMS BER decoder advances its internal read position incorrectly while processing certain fields in a crafted confirmed-request element, causing a heap out-of-bounds read. An established MMS session is required, and successful exploitation terminates the hosting process without reported data disclosure or modification.

CVSS severity7.1
High
EPSS probability0.25%
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 libIEC61850 before 1.6.2 allows remote authenticated users to crash the MMS handling process over TCP port 102. The MMS BER decoder advances its internal read position incorrectly while processing certain fields in a crafted confirmed-request element, causing a heap out-of-bounds read. An established MMS session is required, and successful exploitation terminates the hosting process without reported data disclosure or modification.

The record

CVE
CVE-2026-63550
Published
Jul 30, 2026
Updated
Jul 30, 2026
Vendor
MZ Automation GmbH
Product
libIEC61850
Classifications
CWE-125, T0814
Attack vector
network
Privileges
authenticated

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 vectornetwork
Required privilegesauthenticated

What is affected?

MZ Automation GmbH · libIEC61850version=0 <1.6.2

Published CVSS scores

6.5CISACVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1National Vulnerability DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
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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