He and the victim had apparently dated and recently broken up, but a motive has not been determined.
Authorities confirmed the victim's identity as Kendra Beebe. According to her Facebook page, she is a 35-year-old mother of two who works as an insurance broker in Carlsbad, a coastal suburb.
She was listed in critical condition Monday, according to the San Diego sheriff's department. Spokeswoman Jan Caldwell said Tuesday she had no update on Beebe's condition.
A woman who answered the phone at Beebe's office declined to comment to The Associated Press.
Malil's agent, Mark Measure of Abrams Artist Agency, also declined to comment.
"Malil and the victim had apparently been in a dating relationship which recently ended," the Sheriff's Department said in a prepared statement.
Malil starred in a 2001 Super Bowl commercial for Budweiser beer. He also played a co-worker, Haziz, to comedian Steve Carell's title character in "The 40-Year-Old Virgin."
He had taken the train from Los Angeles to meet his attorney, who has joined the actor's family members and friends in persuading him to turn himself in, deputies said.
Deputies found the victim on Sunday night while responding to reports of screams for help and breaking glass in San Marcos, about 15 miles east of Oceanside.
Malil, who lives in Sherman Oaks, a suburb of Los Angeles, was arrested for investigation of attempted murder, mayhem and burglary and booked into the county's Vista Detention Center, the statement said. He is currently in custody at San Diego's Central Jail.
Attempts to identify and reach his attorney for comment were unsuccessful.
Malil played one of star Steve Carell's co-workers in "The 40-Year-Old-Virgin" and has appeared in dozens of TV shows including "NYPD Blue" and "Scrubs."
The Associated Press contributed to this report