What is CVE-2025-34256?

CVE-2025-34256 is a critical-severity vulnerability in Advantech Wise-Deviceon Server, classified under Use of Hard-coded Cryptographic Key. CVSS score: 9.8/10. Published 2025-12-05.

How severe is CVE-2025-34256?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Advantech Wise-Deviceon Server

CVE-2025-34256

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.

EPSS: 0.006 (46.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Advantech Wise-deviceon_server
Advantech Co., Ltd. Wise-deviceon Server — versions 0

Weakness classification (CWE)

CWE-321 — Use of Hard-coded Cryptographic Key

References

disclosure@vulncheck.com (vendor-advisory, patch)
disclosure@vulncheck.com (technical-description, exploit)
disclosure@vulncheck.com (Product, product)
disclosure@vulncheck.com (Third Party Advisory, third-party-advisory)

Frequently asked questions

What is CVE-2025-34256?: CVE-2025-34256 is a critical-severity vulnerability in Advantech Wise-Deviceon Server, classified under Use of Hard-coded Cryptographic Key. CVSS score: 9.8/10. Published 2025-12-05.
How severe is CVE-2025-34256?: Critical severity. CVSS v3 base score is 9.8 out of 10.