Is my Neff oven leaking ?

I have a Neff 1031 integrated oven, 22 years old. The door seal is fine, but I'm getting air blowing into the cupboard next to the oven, leaving damp and greasy marks on food packets etc......it can only have come from the oven.....any ideas on what is happening? Obviously the oven is old, is it possible there is a leak in the oven housing somewhere? Very grateful for any ideas!