App Crahes on empty VCALENDAR SUMMARY

On a customers iPhone (iOS 11.4.1) my calendar app crashes. We found out that the reason is a Skype-Business Meeting event where the SUMMARY field in the VCALENDAR ist empty:


SUMMARY;LANGUAGE=de-DE:


On my device with same iOS version it is not crashing. The call stack I got via iTunes connect shows a line where my app analyses the event title with range(of searchString: String) which should not be a problem, also if the title is empty. It looks more that there is some memory out of bounds. I´m now waiting for an answer from user, I asked him to assign the event to another calendar (type) when importing a VCALENDAR with this crash.

Replies

Ok, user tested with diffferent calendar types and the app crashes always if SUMMARY ( subject field) is empty.