Service to the news Web site is interrupted for about an hour, but the cause of the outage has not been determined, the company says.
Web users were unable to access CNN.com beginning around 9:30 a.m. PST, but the site was up and running by 10:30 a.m., according to CNN spokeswoman Edna Johnson. CNN is in the process of investigating the cause of the outage, she added, declining to comment further on the matter.
A source within CNN who requested anonymity said there was no indication of any malicious attack, and the outage was likely because of an internal mistake.
The CNN.com stall comes as concerns about hacker attacks have been heightened by recent outages of Microsoft sites.
This week, Microsoft's family of Web sites, including Microsoft.com, Hotmail, MSN.com and Expedia.com, suffered service outages. The software giant on Tuesday and Wednesday blamed an internal glitch for problems and then confirmed Thursday that a denial-of-service attack had crippled its sites.
A denial-of-service attack bombards a Web site's servers with fake requests for information. The servers struggle to keep up with the requests, causing slow service or an outage.
Last February, CNN.com succumbed to a denial-of-service attack that left it crippled for days. The site was one of several high-profile Web sites, including Yahoo, eBay, Amazon.com, Buy.com and E*Trade, that fell victim to the attacks.