CVE-2026-4769: Unauthenticated Access to Internal Diagnostic Interface

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-13 · updated 2026-07-13
Weakness: CWE-912

Description

Certain devices in the WAGO System I/O Field series activate an internal diagnostic capability during the initial startup sequence. This functionality is not formally documented and becomes accessible without authentication for a brief period in the early boot phase. During this window, an unauthenticated remote attacker can gain access to the internal system processes, resulting in full system compromise.

Affected products

WAGO 0765-110x/0100-0000: from 1.0.0.0 before 1.2.1.100 — fixed in 1.2.1.100
WAGO 0765-120x/0100-0000: from 1.0.0.0 before 1.2.7.100 — fixed in 1.2.7.100
WAGO 0765-150x/0100-0000: from 1.0.0.0 before 1.2.7.103 — fixed in 1.2.7.103
WAGO 0765-2101/0100-0000: from 1.0.0.0 before 1.2.1.102 — fixed in 1.2.1.102
WAGO 0765-2102/0100-0000: from 1.0.0.0 before 1.2.5.101 — fixed in 1.2.5.101
WAGO 0765-410x/0100-0000: from 1.0.0.0 before 1.2.1.100 — fixed in 1.2.1.100
WAGO 0765-420x/0100-0000: from 1.0.0.0 before 1.2.7.100 — fixed in 1.2.7.100
WAGO 0765-450x/0100-0000: from 1.0.0.0 before 1.2.7.103 — fixed in 1.2.7.103

How to fix

Upgrade to a fixed version: WAGO 0765-110x/0100-0000 1.2.1.100; WAGO 0765-120x/0100-0000 1.2.7.100; WAGO 0765-150x/0100-0000 1.2.7.103; WAGO 0765-2101/0100-0000 1.2.1.102; WAGO 0765-2102/0100-0000 1.2.5.101; WAGO 0765-410x/0100-0000 1.2.1.100; WAGO 0765-420x/0100-0000 1.2.7.100; WAGO 0765-450x/0100-0000 1.2.7.103. Check the vendor advisory for mitigations.

References

https://www.certvde.com/en/advisories/VDE-2026-031/

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