The Spam protection, Anti-Spam, FireWall by CleanTalk plugin for WordPress is vulnerable to unauthorized Arbitrary Plugin Installation due to an missing empty value check on the 'api_key' value in the 'perform' function in all versions up to, and including, 6.44. This makes it possible for unauthenticated attackers to install and activate arbitrary plugins which can be leveraged to achieve remote code execution if another vulnerable plugin is installed and activated.
The Spam protection, AntiSpam, FireWall by CleanTalk WordPress plugin before 5.185.1 does not validate ids before using them in a SQL statement, which could lead to SQL injection exploitable by high privilege users such as admin
It was possible to exploit an Unauthenticated Time-Based Blind SQL Injection vulnerability in the Spam protection, AntiSpam, FireWall by CleanTalk WordPress Plugin before 5.153.4. The update_log function in lib/Cleantalk/ApbctWP/Firewall/SFW.php included a vulnerable query that could be injected via the User-Agent Header by manipulating the cookies set by the Spam protection, AntiSpam, FireWall by CleanTalk WordPress plugin before 5.153.4, sending an initial request to obtain a ct_sfw_pass_key cookie and then manually setting a separate ct_sfw_passed cookie and disallowing it from being reset.