SeaCMS 12.9 has a remote code execution vulnerability. The vulnerability is due to the fact that although admin_template.php imposes certain restrictions on the edited file, attackers can still bypass the restrictions and write code in some way, allowing authenticated attackers to exploit the vulnerability to execute arbitrary commands and gain system privileges.
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.