Modx Revolution Remote Code Execution
Modx Revolution < 2.6.4 suffers from a Remote Code Execution.
This has been patched by the authors in v 2.6.5, if you are running anything less than 2.6.5 you should upgrade your ModX immediately.
Utilizing a vulnerability in the way Modx handles thumbnail creation in the file
Can allow an attacker to pass exploit data to
Which then allows the attacker to execute remote code execution.
Remote code execution means the attack can invoke system calls and take full control over the system.
This is a very dangerous vulnerability and should be patched immediately.