Can anxiety attacks cause numbness in legs?

No. not directly. There is no true nerve impingement to cause that. However a true panic attack can have a overall sensation that can sometimes feel all over. .
Anxiety symptoms. Anxiety can produce a large range of physical symptoms. For any serious physical symptom I always recommend a full physical from your physician, but if the symptom is caused by the original distressing event(s) then resolving the emotional distress from the event can resolve the physical sx.