Bread is not toxic to cats, but it is not species-appropriate and can lead to obesity if fed regularly.
It may also contain additives like raisins, which are toxic to cats and can cause acute kidney failure.
Suggestions
Bread should only be given as an occasional treat in small amounts.
Avoid bread with toxic additives like raisins.
If your cat shows an unusual appetite for bread, consult a vet as it may indicate underlying health issues.
Note: even if labeled as safe, any food can potentially cause allergies. When introducing a new food, please feed a small amount and observe your cat for any allergic reactions.