CVE-2026-103427: Simple Membership <= 4.8.4 - Authenticated (Subscriber+) Stored Cross-Site Scripting via Country Field
The Simple Membership plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'country' parameter in all versions up to, and including, 4.8.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Unauthenticated attackers may also exploit this vulnerability when the plugin's Enable Free Membership feature is turned on, as it permits anonymous front-end registration and profile submission.
Affected Software
Event History
Frequently Asked Questions
Who can submit a malicious value?
Any authenticated user with Subscriber-level access or higher can exploit the issue. Unauthenticated users can also exploit it if Enable Free Membership is enabled, because that allows anonymous front-end registration and profile submission.
When does the injected script run?
The script executes when a user accesses a page containing the injected content. This can affect users who view the attacker-controlled page after the payload has been stored.
Is anonymous exploitation always possible?
No. The available information identifies anonymous exploitation only when the Enable Free Membership feature is turned on; it does not state whether that feature is enabled by default.