CVE-2025-9495 json
Viessmann Vitogate 300 Authentication Bypass
published 2025-09-23 13 mo ago modified 2026-10-11 28 d ago also EUVD-2025-30428
- cvss
- 8.7
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 15%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Viessmann Vitogate 300 3.0.0.0
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
cisa ICSA-25-266-04 updated cvss 8.8
Viessmann Vitogate 300
-
Viessmann Vitogate 300 <3.1.0.1affected: vendor fix, mitigation “For more information refer to Carrier's product security advisory CARR-PSA-2025-02.” connectivity.viessmann-climatesolutions.com
From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 13 mo ago
Exploit prediction
0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.7 | 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 |
| CNA | 4.0 | 8.7 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- Viessmann Vitogate 300
Classification
- Weakness
-
- CWE-602 Client-Side Enforcement of Server-Side Security
References
Sources
- CVE List CVE-2025-9495
- NVD CVE-2025-9495
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.