At this moment 5.6.33-0 is the latest MAMP version, so all known issues or bugs are already patched.
We release new MAMP versions when the main components present a new version. Also, if the component's developers release a new version including some security fixes, we start working on it as soon as possible to provide a new MAMP version including this component updated (even if they are not the main components of the stack).
In your case, at this moment, you're up to date.
Carlos R. Hernández