"She and her team and their security were surrounded by a dangerous element amidst the celebration. It was a mob of more than 200 people whipped into a frenzy," CBS said in a statement.
"In the crush of the mob, she was separated from her crew. She was surrounded and suffered a brutal and sustained sexual assault and beating before being saved by a group of women and an estimated 20 Egyptian soldiers."
The incident took place on Cairo's central Tahrir Square last Friday, the day Mubarak stepped down, CBS said.
The assault lasted for around 20 to 30 minutes, an insider told the Wall Street Journal, though they stated that it was "not a rape".
Logan was flown to the United States the next day where she was admitted to hospital.
South African-born Logan has covered the conflicts in Iraq and Afghanistan, becoming one of the US media's most recognisable war correspondents.
She became CBS News chief foreign correspondent in 2006 after starting at the network four years earlier.
The mother of two young children, Logan met her husband, a defence contractor, while working as a correspondent in Iraq.
She had been in Egypt to cover the celebrations after Mubarak's resignation for news program 60 Minutes.