Vulnerability · Published Dec 5, 2025 · Assigned by VulnCheck
CVE-2025-34256Advantech WISE-DeviceOn Server < 5.4 Hard-coded JWT Key Authentication Bypass
Critical 10.0
In plain English
A critical-severity security flaw in WISE-DeviceOn Server from Advantech Co., Ltd.. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 55% of all known vulnerabilities).
Official description
Advantech WISE-DeviceOn Server versions prior to 5.4 contain a hard-coded cryptographic key vulnerability. The product uses a static HS512 HMAC secret for signing EIRMMToken JWTs across all installations. The server accepts forged JWTs that need only contain a valid email claim, allowing a remote unauthenticated attacker to generate arbitrary tokens and impersonate any DeviceOn account, including the root super admin. Successful exploitation permits full administrative control of the DeviceOn instance and can be leveraged to execute code on managed agents through DeviceOn’s remote management features.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Advantech Co., Ltd. | WISE-DeviceOn Server | 0 – before 5.4.0 |
Weakness: CWE-321 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
References
- https://advcloudfiles.advantech.com/cms/2ca1b071-fd78-4d7f-8a2a-7b4537a95d19/Security%20Advisory%20PDF%20File/SECURITY-ADVISORY----DeviceOn-20251208-2.pdf vendor-advisory, patch
- https://pellera.com/blog/advantech-wise-deviceon-cve-2025-34256-vulnerability/ technical-description, exploit
- https://docs.deviceon.advantech.com/docs/resource/ product
- https://www.vulncheck.com/advisories/advantech-wise-deviceon-server-hardcoded-jwt-key-authentication-bypass third-party-advisory