CVE-2026-66364: Mz Automation GmbH LIBIEC61850

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

The GOOSE payload parser contains a boundary handling flaw that can be triggered by a single unauthenticated Layer 2 multicast frame on the process bus. When processing specific payload fields, an attacker controlled inner element length may exceed its enclosing length, causing the parser to over read by one byte. This out-of-bounds read reliably terminates the subscriber process, resulting in a denial-of-service condition.

Affected products

• Mz Automation GmbH LIBIEC61850: before 1.6.2 (fixed in 1.6.2)

Published 2026-07-30. Last modified 2026-09-03.