CVE-2025-34256

Advantech WISE-DeviceOn Server < 5.4 Hard-coded JWT Key Authentication Bypass

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

Advantech Co., Ltd. · WISE-DeviceOn Server

CVSS v4.0 VULNCHECK

10.0 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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

CVSS v3.1 NVD

9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

0.69% chance of exploitation in the next 30 days, 52nd percentile

Published

2025-12-05

Updated

2026-08-14

Proof-of-concept exploits (1)

• https://pellera.com/blog/advantech-wise-deviceon-cve-2025-34256-vulnerability/

Security advisories

• https://www.vulncheck.com/advisories/advantech-wise-deviceon-server-hardcoded-jwt-key-aut…
• https://docs.deviceon.advantech.com/docs/resource

References

• CVE Record
• NVD entry