Service crash via extended BER tag
Published Jul 30, 2026 · Updated Jul 30, 2026
Out-of-bounds read in the MMS server connection handler in MZ Automation libIEC61850 before 1.6.2 allows remote attackers to crash the service. The BER decoder advances its internal buffer incorrectly when an MMS confirmed request PDU contains an extended tag, because the handler omits a bounds check and reads one byte beyond the heap buffer. An established MMS session from the adjacent network is required; the resulting read terminates the MMS service process.
Summary
What happened
Out-of-bounds read in the MMS server connection handler in MZ Automation libIEC61850 before 1.6.2 allows remote attackers to crash the service. The BER decoder advances its internal buffer incorrectly when an MMS confirmed request PDU contains an extended tag, because the handler omits a bounds check and reads one byte beyond the heap buffer. An established MMS session from the adjacent network is required; the resulting read terminates the MMS service process.
The record
- CVE
- CVE-2026-66349
- Published
- Jul 30, 2026
- Updated
- Jul 30, 2026
- Vendor
- MZ Automation GmbH
- Product
- libIEC61850
- Classifications
- CWE-125, T1499.004
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 30, 2026CVE publishedPublication date reported by the CVE source.
- 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?
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- Affected versionversion=0 <1.6.2
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What is affected?
Published CVSS scores
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Attacks
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Technologies
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Your stack
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