CVE-2025-34266 Advantech WISE-DeviceOn Server < 5.4 Authenticated Stored XSS via plugin-config/addins/menus

Q: What is CVE-2025-34266?

CVE-2025-34266 is a medium-severity cross-site scripting vulnerability in Advantech Co., Ltd. WISE-DeviceOn Server, published on 5 Dec 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Q: Is CVE-2025-34266 being exploited?

There is no known exploitation of CVE-2025-34266 in the wild and no public exploit code.

Q: How do I fix CVE-2025-34266?

No fix has been published for CVE-2025-34266 yet. Limit exposure of the affected software until one is available.

Medium 5.1 Published 5 Dec 2025 Updated 14 Aug 2026

Authenticated attackers can inject malicious scripts into AddIns menu entries, leading to session compromise and unauthorized actions for other users.

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: None listed

What is CVE-2025-34266?

CVE-2025-34266 is a medium-severity cross-site scripting vulnerability in Advantech Co., Ltd. WISE-DeviceOn Server, published on 5 Dec 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 WISE-DeviceOn Server versions prior to 5.4 contain a stored cross-site scripting (XSS) vulnerability in the /rmm/v1/plugin-config/addins/menus endpoint. When an authenticated user adds or edits an AddIns menu entry, the label and path values are stored in plugin configuration data and later rendered in the AddIns UI without proper HTML sanitation. An attacker can inject malicious script into either field, which is then executed in the browser context of users who view or interact with the affected AddIns entry, potentially enabling session compromise and unauthorized actions as the victim.

Weakness: CWE-79

Which versions are affected by CVE-2025-34266?

It affects 1 product.

Products include Advantech Wise-Deviceon Server.

How do I fix CVE-2025-34266?

No fix has been published for CVE-2025-34266 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-34266 being exploited?

There is no known exploitation of CVE-2025-34266 in the wild and no public exploit code.

Sources

Also known as GHSA-r3qf-jhw8-r9hq.