Personal details such as email addresses and passwords for up to 360 employees of broadcast giant Fox could be published on the internet within days.
Hackers claiming to have stolen the details appeared to have manipulated LinkedIn profiles owned by a dozen Fox staff as proof of the attack.
The group, LulzSec, published links to the hacked profiles on Twitter and promised to disclose the full list of email accounts and passwords if a message was retweeted 100 times.
Aklthough the attacks were not verified, Fox news broadcast affiliate WTLH confirmed the name of an employee whose LinkedIn profile appeared to be hacked.
LulzSec also claimed responsibility for stealing 250,000 personal details for contestants of Fox TV show X-Factor and later publishing them on a BitTorrent website.
SC Magazine can not confirm if the breaches were from the same attack.
LulzSec, which described itself as a "team of lulzy individuals who feel the drabness of the cyber community is a burden on fun”, promised to release data from more breaches.