CVE-2025-34257Network attack vector

Authenticated stored XSS via unsanitized task name

Published Dec 5, 2025 · Updated Aug 14, 2026

Stored XSS in Advantech WISE-DeviceOn Server before 5.4 allows remote authenticated users to hijack viewer sessions via crafted task names. The /rmm/v1/action/defined endpoint stores defined_name, and the Overview page renders that value without HTML sanitization. Task-creation access is required, and execution occurs only when another user views the affected task, enabling actions in that user's browser context.

CVSS severity5.1
Medium
EPSS probability0.26%
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 hijack viewer sessions via crafted task names. The /rmm/v1/action/defined endpoint stores defined_name, and the Overview page renders that value without HTML sanitization. Task-creation access is required, and execution occurs only when another user views the affected task, enabling actions in that user's browser context.

The record

CVE
CVE-2025-34257
Published
Dec 5, 2025
Updated
Aug 14, 2026
Vendor
Advantech
Product
DeviceOn Server
Classifications
CWE-79, T1189
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

5.4NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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/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 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')
T1189Drive-by Compromise

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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