EXCLUSIVE

The Oscars fallout is getting scary for the PricewaterhouseCoopers employees responsible for the Best Picture debacle -- they're in such fear for their lives, their bosses have hired security to protect them.

Sources connected to the firm tell TMZ ... PWC decided bodyguards were necessary for Brian Cullinan, Martha Ruiz and their families because of death threats they've received after their role in fumbling the Best Picture and Best Actress envelopes.

Some of the social media threats included, "You f****** idiot, i will f*** you every day" ... and "I hope you get fired and get cancer."

We're told PWC felt pictures that surfaced online of Ruiz and Cullinan's homes made it clear something had to be done to watch their backs.