An app could impersonate system notifications. Sensitive notifications now require restricted entitlements. This issue is fixed in iOS 18.3 and iPadOS 18.3, iPadOS 17.7.3. An app may be able to cause a denial-of-service.
https://github.com/TS0NW0RK/DFURoulette
https://github.com/rooootdev/evilnotify