Security firm Symantec says it has discovered a security flaw in Facebook that inadvertently gives advertisers and other outside parties access to people's accounts. But Facebook says it has fixed the problem and found no evidence that any private information was shared with any outside party.

Symantec said Tuesday that the outside parties may not have realized that they were able to access users' profiles, photos and chats. The security firm estimates that some 100,000 applications were enabling the data leak.

Symantec says the problem was leaking "access tokens" — akin to spare keys. They let apps access your profile if you gave them permission.