CVE-2025-9495 - CVE House
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Status published High CVE-2025-9495

Viessmann Vitogate 300 Authentication Bypass

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • Souvik Kandar of MicroSec (microsec.io)

References

More from Viessmann

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CVE-2025-9494
Viessmann Vitogate 300 OS Command Injection
High 8.5
CVE-2023-5702
Viessmann Vitogate 300 direct request
Medium 4.3
CVE-2023-5222
Viessmann Vitogate 300 Web Management Interface vitogate.cgi isValidUser hard-coded password
Medium 6.3

Affected Vendor

Affected Software

Vitogate 300
Vulnerable Versions:
1

Timeline

Official Publish: September 23rd, 2025
Last Modified: September 23rd, 2025
Added to House: July 22nd, 2026

CVSS Vectors

Weaknesses (CWE)

CWE-602

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.