The DNC regularly polls its users on political issues via its Web site. Earlier today, the Center for the Study of Technology and Society, an online security watchdog organization, said the DNC site keeps a log of users' Internet protocol (IP) addresses, which could be read online by anyone with a Web browser.
An IP address is a unique string of numbers that identifies a computer on the Internet.
The DNC said it wasn't aware of the problem until the center publicized it in a press release. A DNC representative said the organization remedied the problem by moving software and data from an unsecured server to a secure server.
IP addresses can be used to monitor online browsing and other personal information. A directory of IP addresses viewable online could make users' computers vulnerable to attack, the center said.
"Collecting user IP addresses is bad enough, but publishing them online poses a serious danger to unsuspecting users," Adam Keiper, president of the center, said in a statement.