CVE-2026-103899: EU VAT Assistant for WooCommerce <= 2.1.30.260413 - Unauthenticated Stored Cross-Site Scripting via 'vat_number' Parameter
The EU VAT Assistant for WooCommerce plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'vatnumber' parameter in all versions up to, and including, 2.1.30.260413 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The stored payload executes in the administrator's browser context when reviewing an order via WooCommerce → Orders → Edit Order, enabling privilege escalation up to and including full site takeover via rogue administrator account creation.
Affected Software
Event History
Frequently Asked Questions
Which installations are affected?
Aelia EU VAT Assistant for WooCommerce versions up to and including 2.1.30.260413 are affected.
Does exploitation require an authenticated WordPress or WooCommerce account?
No. An unauthenticated attacker can submit a malicious payload through the vat_number parameter.
When does the injected script execute?
The payload is stored and executes when an administrator reviews the affected order in WooCommerce under Orders → Edit Order. It runs in that administrator's browser context.
What is the practical impact if an administrator views a malicious order?
An attacker can execute arbitrary web scripts in the administrator's session and escalate privileges, including creating a rogue administrator account and taking over the site.