Critical CVE-2026-4769 Vulnerability in WAGO Devices Exposes Systems to Remote Attacks

This report describes CVE-2026-4769, a critical (CVSS 9.8) vulnerability in WAGO System I/O Field devices where an undocumented diagnostic interface becomes accessible during startup for a short window, enabling unauthenticated remote attackers to access internal processes and potentially fully compromise devices; no public PoC or exploitation has been observed and no patch is currently available, so the report recommends monitoring startup network access and securing or isolating affected devices.