Can I Give My Cat generic 100% pumpkin?

Yes, with care
Canned pumpkin (plain) is commonly referenced for cats at published doses. Published guidance for cats: 1/2 - 1 tsp per meal, with meals. Same warning: 100% pumpkin only.
Source: Veterinary Partner (VIN)
Get the exact range for your cat's weight

Skip it or ask a vet first if

pumpkin pie filling

The safe habit

Confirm any medication decision with your veterinarian, who knows your cat's health history and other medications. VetDose shows published reference data, not prescriptions.