Sahih al-Bukhari 2829
صحيح البخاري#2829SahihNarrated Abu Huraira:Allah's Messenger (ﷺ) said, "Five are regarded as martyrs: They are those who die because of plague, Abdominal disease, drowning or a falling building etc., and the martyrs in Allah's Cause
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 56:45