CVE-2026-66349

MZ Automation libiec61850 Out-of-bounds Read

Published Jul 30, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
Description
The MMS server connection handler contains a flaw in its processing of
BER-encoded request data. When an MMS confirmed request PDU containing
an extended BER tag is received over an established session, the decoder
may advance its internal buffer incorrectly due to a missing bounds
check. This results in a one byte heap out-of-bounds read and causes the
MMS service process to terminate, leading to a denial-of-service
condition.

Remediation

Vendor Solution

MZ Automation GmbH recommends that users update to version 1.6.2.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Mz-automation
Mz-automation libiec61850
Vendors & Products Mz-automation
Mz-automation libiec61850
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description The MMS server connection handler contains a flaw in its processing of BER-encoded request data. When an MMS confirmed request PDU containing an extended BER tag is received over an established session, the decoder may advance its internal buffer incorrectly due to a missing bounds check. This results in a one byte heap out-of-bounds read and causes the MMS service process to terminate, leading to a denial-of-service condition.
Title MZ Automation libiec61850 Out-of-bounds Read
Weaknesses CWE-125
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
icscert
Published
Updated
Jul 31, 2026, 3:54 PM
Reserved
Jul 27, 2026, 7:32 PM
Status
Deferred
Published
Jul 30, 2026, 11:16 PM
Modified
Oct 23, 2026, 11:10 PM