Police were called to the address in Ashington in the early hours of this morning, where they found the 20-year-old man with stab wound to the chest.
Three people have since been arrested on suspicion of wounding, and police are appealing for information about the incident.
The man is reported to be a in a critical but stable condition.
More top news
Ian Stewart reported his fiancé missing last April after suffocating her and dumping her body in a cesspit, in a murder motivated by money
Northumbrian author Helen Bailey believed Ian Stewart was her “happy ending”. He was anything but, as he brutally ended her life.
Polly and Lolly have been friends for over 17 years. Both still work in the region.