CVE-2025-34256 json
Advantech WISE-DeviceOn Server < 5.4 Hard-coded JWT Key Authentication Bypass
published 11mo ago modified 2mo ago also EUVD-2025-201428
- cvss
- 9.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 54%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Advantech Co., Ltd. WISE-DeviceOn Server 5.4.0
Is CVE-2025-34256 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- total
- Assessed
- 6mo ago
Exploit prediction
0.74% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- pellera.com https://pellera.com/blog/advantech-wise-deviceon-cve-2025-34256-vulnerability/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 10.0 | 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 |
| CNA | 4.0 | 10.0 | 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/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 |
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
- Advantech Co., Ltd. WISE-DeviceOn Server
Classification
- Weakness
-
- CWE-321 Use of Hard-coded Cryptographic Key
References
-
advcloudfiles.advantech.com
/cms/2ca1b071-fd78-4d7f-8a2a-7b4537a95d19/Security%20Advisory%20PDF%20File/SECURITY-ADVISORY----DeviceOn-20251
vendor-advisory, patch
-
pellera.com
/blog/advantech-wise-deviceon-cve-2025-34256-vulnerability/
technical-description, exploit
-
docs.deviceon.advantech.com
/docs/resource/
product
-
vulncheck.com
/advisories/advantech-wise-deviceon-server-hardcoded-jwt-key-authentication-bypass
third-party-advisory
Sources
- CVE List CVE-2025-34256
- NVD CVE-2025-34256
Fencer Intel 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.