dbcve.org
Webaccess\/vpnApplication · Advantech

CVE-2025-34237

MEDIUM · 5.4 CVSS v3.1 Published 2025-11-06
Fix available
A fix is available. Upgrade to 1.1.5 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Advantech WebAccess/VPN versions prior to 1.1.5 contain a stored cross-site scripting (XSS) vulnerability via StandaloneVpnClientsController.addStandaloneVpnClientAction(). Insufficient validation or escaping of user-supplied input may allow an attacker to inject and execute arbitrary script in the context of a victim's browser.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Advantech WebAccess/VPN versions prior to 1.1.5 contain a stored XSS vulnerability in the StandaloneVpnClientsController.addStandaloneVpnClientAction() function. The application fails to properly validate or escape user-supplied input, allowing attackers to inject malicious scripts that persist and execute in victims' browsers.

MitigationUpgrade to WebAccess/VPN version 1.1.5 or later. Additionally, implement proper input validation and output encoding for the VPN client input fields to prevent XSS.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Webaccess\/vpnApplication
Affected:< 1.1.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed WebAccess/VPN version
    Locate the WebAccess/VPN installation and check the version information, typically found in the application GUI, installer properties, or installation directory metadata
    Affected if The installed version is any release prior to 1.1.5
  2. Verify presence of VPN client management module
    Check if the StandaloneVpnClientsController component exists in the WebAccess/VPN installation, typically found in the application's controller or module directory
    Affected if The addStandaloneVpnClientAction function is present in the application
  3. Confirm access to VPN client addition interface
    Determine if the web interface includes functionality to add standalone VPN clients - this is the entry point where the vulnerable function processes input
    Affected if Users with access to add VPN clients can submit input to the application
  4. Inspect VPN client input handling
    Examine the application's handling of VPN client input fields (such as client name, IP address, or description fields) to see if input validation or encoding is applied before storage
    Affected if Input fields for VPN client creation lack proper validation or output encoding mechanisms

The environment is affected if WebAccess/VPN version is below 1.1.5 AND the VPN client management feature is accessible to users, since the stored XSS vulnerability exists in the addStandaloneVpnClientAction function that processes client input without proper sanitization.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.1.5 or later
Fixed in 1.1.5
Interim mitigation

Upgrade to WebAccess/VPN version 1.1.5 or later. Additionally, implement proper input validation and output encoding for the VPN client input fields to prevent XSS.

Recommended fix High confidence

WebAccess/VPN 1.1.5

  1. 1. Identify all deployments of Advantech WebAccess/VPN in your environment
  2. 2. Verify current installed version using the system administration interface or command line tools
  3. 3. Obtain WebAccess/VPN version 1.1.5 or later from the official Advantech download repository (icr.advantech.com)
  4. 4. Before upgrading, back up the current configuration and any critical data
  5. 5. Apply the upgrade following the vendor's documented upgrade procedure
  6. 6. After upgrade, verify the new version is correctly installed
  7. 7. Test the addStandaloneVpnClientAction functionality to confirm XSS input is properly validated/escaped

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Webaccess\/vpn Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-34237 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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