The music mogul is accused of grabbing Megan Hauserman, 26, by the hair and refusing to let go during filming of VH1 series Rock of Love: Charm School.
Celebrity news website TMZ said police in Los Angeles are investigating the "brutal cat fight" during the reunion show.
Hauserman, already a veteran of a number of reality shows and a Playboy model, said Osbourne, 56, attacked her on Saturday after she made a joke about Ozzy Osbourne.
Well she has got the f***ing brain of a peanut. She does have a pretty damn good body, but no f***ing brain.
Hauserman is reported to have told Osbourne she was only famous "for managing a brain dead rock star".
It is alleged that Osbourne then ran across the stage, grabbed Hauserman by the hair and scratched her until the pair were separated by security.
Hauserman reportedly went to hospital on Sunday and then made a report to police later that night.
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