# CVE-2025-34237: Advantech WebAccess/VPN < 1.1.5 Stored XSS via StandaloneVpnClientsController.addStandaloneVpnClientAction()

> Attackers can inject malicious scripts into the WebAccess/VPN interface, potentially hijacking user sessions or executing code in victims' browsers.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 6 Nov 2025
- **Updated:** 17 Nov 2025
- **Also known as:** GHSA-c27p-92mm-fc82

## What is CVE-2025-34237?

CVE-2025-34237 is a medium-severity cross-site scripting vulnerability in Advantech WebAccess/VPN, published on 6 Nov 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2025-34237?

It affects 1 product.


Products: Advantech Webaccess\/Vpn.

## How do I fix CVE-2025-34237?

No fix has been published for CVE-2025-34237 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-34237 being exploited?

There is no known exploitation of CVE-2025-34237 in the wild and no public exploit code.

## Other vulnerabilities in Advantech WebAccess/VPN

- [CVE-2025-34239](https://insights.sbomify.com/CVE-2025-34239/): Advantech WebAccess/VPN < 1.1.5 Command Injection in AppManagementController.appUpgradeAction() (high 8.6)
- [CVE-2025-34240](https://insights.sbomify.com/CVE-2025-34240/): Advantech WebAccess/VPN < 1.1.5 SQL Injection via AppManagementController.appUpgradeAction() (high 8.6)
- [CVE-2025-34242](https://insights.sbomify.com/CVE-2025-34242/): Advantech WebAccess/VPN < 1.1.5 SQL Injection via AjaxNetworkController.ajaxAction() (high 8.6)
- [CVE-2025-34238](https://insights.sbomify.com/CVE-2025-34238/): Path traversal in WebAccess/VPN (medium 6.9)
- [CVE-2025-34236](https://insights.sbomify.com/CVE-2025-34236/): Advantech WebAccess/VPN < 1.1.5 Stored XSS via NetworksController.addNetworkAction() (medium 6.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-34237 and fix it if it is affected.

What it is: CVE-2025-34237 is a medium-severity cross-site scripting vulnerability in Advantech WebAccess/VPN, published on 6 Nov 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-34237 in the wild and no public exploit code.

Affected product: Advantech WebAccess/VPN. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-34237/ (Markdown: https://insights.sbomify.com/CVE-2025-34237/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-34237
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-34237
- OSV: https://osv.dev/vulnerability/CVE-2025-34237

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-34237/
Summaries are generated and may contain mistakes; the official description above is the record.