What’s Vulnerable › Vulnerabilities

CVE-2026-66349: MZ Automation libiec61850 Out-of-bounds Read

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-30 · updated 2026-10-23
• Weakness: CWE-125

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.

Affected products

• mz-automation libiec61850: before 1.6.2 — fixed in 1.6.2

How to fix

Upgrade to a fixed version: mz-automation libiec61850 1.6.2. Check the vendor advisory for mitigations.

References

• https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-211-10.json
• https://www.cisa.gov/news-events/ics-advisories/icsa-26-211-10

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