Originally posted by Cats:

Someone manage to find a bug into the server I staff for. Then they mass spawned a bunch of weapons from this addon. Does anyone have any knowledge about the bug/exploit that allows people to spawn items as user.??

There shouldn't be any function coming from this weapon specifically that would allow specifically uesrs to create new weapon entities.
Check if they are exploiting item drop functions, such as NPC weapon drops and if they somehow managed to abuse that.
Related cvars are sfw_allow_supplydrop and sfw_supplydrop_chance_weapons

I'll do some testing myself, but it's possible that it's not related to my addon specifically.