A lot of security holes was found in XOOPS with not only 3rd party's modules, but also with core.
I've just released a new module named Xoops Protector.
Major vulnerablities will be patched by installing this module.
I recommend this module to all XOOPS users.
However, you have to know "Almost" is different from "All".
Overconfidence is a taboo.
In fact, Xoops Protector has non-sense against CSRF attacks.
For your security, the best way is to install only the modules made by well-skilled developpers.
BTW, Xoops Protector also has a feature of anti-DoS.
This means that developping of AntiDoS-P was finished.
If you use AntiDoS-P, replace it.
You can download it from downloads area.