Vulnerability · Published Sep 23, 2025 · Assigned by Carrier
CVE-2025-9495Viessmann Vitogate 300 Authentication Bypass
High 8.7
In plain English
A high-severity security flaw in Vitogate 300 from Viessmann. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).
Official description
The Vitogate 300 web interface fails to enforce proper server-side authentication and relies on frontend-based authentication controls. This allows an attacker to simply modify HTML elements in the browser’s developer tools to bypass login restrictions. By removing specific UI elements, an attacker can reveal the hidden administration menu, giving them full control over the device.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Viessmann | Vitogate 300 | 1 – before 3.0.0.0 |
Weakness: CWE-602 · Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N