Is this a gas leak from back the back of my oven and is it dangerous?
Yes it is a leak, a slow leak but a leak nonetheless and it does need to be addressed.

Any leak no matter how small is potentially dangerous. You should turn the valve off And address the problem. 

Some jurisdictions require that all gas connections be handled by a licensed contractor but if you are allowed then you could turn the gas off, use two adjustable wrenches to disconnect the supply line from the fitting,  clean it up with a brush and apply pipe dope to the threads and reattach.

Retest with soapy water after you have finished reconnecting.