Gardaí believe the assault occurred at approximately 5.45pm on Wednesday evening by a local property where some individuals were socialising.
The injured man had staggered onto the roadway where he was discovered by Gardaí and paramedics.
It is understood he had suffered a significant blood loss.
He was given emergency medical treatment at the scene before being rushed by ambulance to CUH.
The man underwent emergency surgery and remains in a critical but stable condition.
A garda spokesman said officers are continuing to appeal to any person who may have witnessed this incident to contact them.
“Any person who was in the vicinity of Glenwood Estate, Carrigaline, between 5p.m. and 5.45p.m. on Wednesday evening 28th December 2022, particularly any road users who may have camera footage (including dash cam) of the incident, is asked to contact investigating Gardaí.
“Anyone with information in relation to this incident is asked to contact Togher Garda Station on 021 494 7120, the Garda Confidential Line on 1800 666 111, or any Garda station.”