Gardaí are investigating an alleged assault on a man in his 20s at the Oxegen music festival in Naas.
The incident happened at around midnight in a car park outside the venue.
The man was brought to Naas General Hospital and transferred to St James's Hospital in Dublin where his condition is said to be stable.
A man in his 20s, who was arrested in connection with the alleged assault has been released without charge.
A file is being prepared for the Director of Public Prosecutions.
Anyone with information has been asked to contact Naas Garda station on 045 88 4 300.
Some 80,000 people are attending the music festival.
There have been 77 arrests since Thursday afternoon for offences including public order, road traffic and offences under the Misuse of Drugs Act.