Jami` at-Tirmidhi 1063
جامع الترمذي#1063SahihAbu Hurairah narrated that:The Messenger of Allah said: "The martyrs are five: Those who die of the plague, stomach illness, drowning, being crushed, and the martyr in the cause of Allah
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 10:99