Thames Valley Police is appealing for witnesses following an assault in Amersham on Monday.
Two men were involved in an altercation in the car park outside Kwikfit in White Lion Road at 9.50am.
One of the men was armed with a weapon and the other man, who is aged in his forties, suffered numerous serious cuts to his body and face.
The victim was taken to the John Radcliffe Hospital in Oxford for further treatment, where he remains in a stable condition.
The offender is described as a bald, white man, aged in his late forties, wearing a baggy black T-shirt and black shorts. They were also driving a white Luton van.
Detective Sergeant Jo Lynch, of Amersham CID, said: “I understand this assault may cause some concern but we are investigating it as a priority.
“It is thought to have been a targeted attack so there is not considered to be any danger to the wider public.
“We are asking anyone who may have witnessed the assault or anything related to it to please come forward.
“It happened during the morning so there may well be many members of the public who witnessed the attack, who I would ask to get in touch.
"We are also asking anyone who lives in the area who has a CCTV camera, or anyone with a dashcam who was driving in the area to please check their recordings and get in touch if it shows anything that may be of use for our investigation.
“Anyone with information or footage can report through our online pages or call 101, quoting reference number 43230430098.
“Alternatively, you can provide information anonymously to the independent charity, Crimestoppers, on 0800 555 111.”