The company's confirmation came following reports that a Russian hacker site posted some 6.5 million LinkedIn passwords, CBS News reported Wednesday.
"Some of the passwords that were compromised correspond to LinkedIn accounts," the company said, noting that the hacker uploaded passwords but not user names.
LinkedIn users use the site to post their resumes and connect with others in business and industry.
"We are continuing to investigate this situation and here is what we are pursuing as far as next steps for the compromised accounts," LinkedIn director Vicente Silveira said in a company blog post.
Members with accounts associated with the compromised passwords will notice that their LinkedIn account password is no longer valid, Silveira said, and those members would receive an e-mail from the company with instructions on how to change their passwords.
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