CVE-2025-34266Network attack vector

Authenticated stored XSS via unsanitized AddIns fields

Published Dec 5, 2025 · Updated Aug 14, 2026

Stored XSS in Advantech WISE-DeviceOn Server before 5.4 allows remote authenticated users to execute scripts in other users' browsers. The AddIns menu endpoint stores attacker-controlled label and path values, then renders them in the AddIns UI without HTML sanitization. Low-privileged account access and another user's interaction are required; successful execution can compromise that user's session and actions.

CVSS severity5.1
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Advantech WISE-DeviceOn Server before 5.4 allows remote authenticated users to execute scripts in other users' browsers. The AddIns menu endpoint stores attacker-controlled label and path values, then renders them in the AddIns UI without HTML sanitization. Low-privileged account access and another user's interaction are required; successful execution can compromise that user's session and actions.

The record

CVE
CVE-2025-34266
Published
Dec 5, 2025
Updated
Aug 14, 2026
Vendor
Advantech
Product
DeviceOn Server
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <5.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Advantech · DeviceOn Serverversion=0 <5.4

Published CVSS scores

5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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