baserCMS is a website development framework. Prior to version 5.2.3, a public mail submission API allows unauthenticated users to submit mail form entries even when the corresponding form is not accepting submissions. This bypasses administrative controls intended to stop form intake and enables spam or abuse via the API. This issue has been patched in version 5.2.3.

Affected: Packagist: baserproject/basercms

### Summary A public mail submission API allows unauthenticated users to submit mail form entries even when the corresponding form is not accepting submissions. This bypasses administrative controls intended to stop form intake and enables spam or abuse via the API.

### Details In baserCMS, mail form submissions through the front-end UI are guarded by acceptance checks implemented in `MailFrontService::isAccepting()`, which ensures that the mail form is currently accepting submissions (e.g. within its configured publish/acceptance window).

These checks are enforced in the UI flow handled by `MailController::index()` and `MailController::confirm()` (e.g. `plugins/bc-mail/src/Controller/MailController.php`).

However, the public API endpoint:

`plugins/bc-mail/src/Controller/Api/MailMessagesController.php::add()`

does not invoke `MailFrontService::isAccepting()` and does not verify whether the mail form is currently accepting submissions. As a result, the API accepts submissions regardless of the form’s acceptance state.

The endpoint does not require authentication. A valid CSRF cookie and token pair is sufficient to create a mail message. This allows submissions even when administrators intentionally disable or close the mail form via the admin UI.

### PoC 1. In the admin UI, configure a mail form so that it is **not accepting submissions** (e.g. outside its acceptance period or explicitly closed). 2. Obtain a CSRF cookie by accessing the site root: ``` curl -sS -D - -…