CVE-2026-100316: European VAT Compliance Assistant for WooCommerce <= 1.36.10 - Unauthenticated Stored Cross-Site Scripting via CF-IPCountry Header
The European VAT Compliance Assistant for WooCommerce plugin for WordPress is vulnerable to Stored Cross-Site Scripting via CF-IPCountry Header in all versions up to, and including, 1.36.10 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 malicious header value is persisted verbatim into order post-meta during a guest checkout, meaning no account or authentication is required to plant the payload.
Affected Software
Event History
Frequently Asked Questions
Who can exploit this issue, and what access do they need?
Any unauthenticated remote attacker can attempt exploitation. They only need to submit a guest checkout with a malicious CF-IPCountry HTTP header; no WordPress account or prior authentication is required.
Are sites using guest checkout exposed?
Yes. The malicious header value is stored in order post-meta during a guest checkout, so installations that allow guest checkout provide the described path for planting a payload.
What user interaction triggers the malicious script?
The injected script executes when a user accesses a page that renders the injected stored value. The provided data does not identify which user roles or specific order-related pages display that value.
How can administrators determine whether they may already be affected?
Review order post-meta created through guest checkouts for unexpected or script-like values in data derived from the CF-IPCountry header. The vulnerable behavior stores the header value verbatim.
What can be done if an update is not immediately available?
As an interim mitigation, restrict or disable guest checkout where operationally feasible, since the documented injection path relies on a guest checkout. Also review and remove suspicious stored values from affected order post-meta.