多说社会化评论框 <= 1.2 - Unauthenticated Privilege Escalation via api.php 'option'/'value' Parameters

The 多说社会化评论框 plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2. The vulnerability exists due to a missing capability and nonce check on a directly web-accessible API endpoint, combined with a trivially forgeable HMAC-SHA1 signature keyed on an always-empty WordPress option, which allows the endpoint's update_option handler to pass attacker-controlled option and value parameters directly to WordPress's update_option function without any allowlist or sanitization. This makes it possible for unauthenticated attackers to update arbitrary WordPress options — such as setting default_role to administrator and enabling open registration — and subsequently register an account with full administrator privileges.