CVE-2026-66349: MZ Automation libiec61850 Out-of-bounds Read
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
MZ Automation GmbH MMS service / libiec61850to a version that resolves this vulnerability.Fixed in 1.6.2
Event History
Frequently Asked Questions
What is the severity of CVE-2026-66349?
The severity of CVE-2026-66349 is rated as medium with a score of 6.5.
What type of vulnerability is CVE-2026-66349?
CVE-2026-66349 is an out-of-bounds read vulnerability in the MZ Automation LibIEC61850.
How do I fix CVE-2026-66349?
To mitigate CVE-2026-66349, update the MZ Automation LibIEC61850 software to the latest version that addresses this issue.
What can be exploited in CVE-2026-66349?
CVE-2026-66349 can be exploited through the processing of BER-encoded request data via the MMS server connection handler.
Is there a risk of data loss with CVE-2026-66349?
Yes, there is a risk of denial of service due to potential data corruption in the MZ Automation LibIEC61850 related to CVE-2026-66349.