CVE-2025-9494: Viessmann Vitogate 300

High severity, CVSS 8.5. EPSS: 0.7% chance of exploitation in the next 30 days.

An OS command injection vulnerability has been discovered in the Vitogate 300, which can be exploited by malicious users to compromise affected installations. Specifically, the `/cgi-bin/vitogate.cgi` endpoint is affected, when the `form` JSON parameter is set to `form-0-2`. The vulnerability stems from the fact that that function at offset 0x21c24 does not properly sanitize supplied input before interpolating it into a format string which gets passed to `popen()`. Consequently, an authenticated attacker is able to inject arbitrary OS commands and thus gain code execution on affected devices.

Affected products

• Viessmann Vitogate 300: from 1, before 3.1.0.0 (fixed in 3.1.0.0)

Published 2025-09-23. Last modified 2026-06-17.