Google has fixed a cross-scripting flaw that opened user accounts to hijacking, the search giant confirmed Monday.

According to San Jose, Calif.-based security vendor Finjan Software, the bug in two unnamed Google sub-sites could have allowed attackers to grab a Google user's cookie. If the user was currently logged on with their Google account -- necessary to use Google's Gmail and new RSS Reader, for instance -- the stolen cookie would have let the attacker access some Google services, including viewing the user's saved searches or alerts, and/or use their identity in Google Groups.

"The cross site scripting vulnerability could have allowed a remote attacker to take over victims’ Google Accounts, or fake the site’s content in order to deceive end users into downloading malicious content or providing personal and confidential information," said Limor Elbaz, Finjan's vice president of business development, in a statement.

Finjan said that it informed Google of the vulnerability in late September, and provided the search giant with proof-of-concept code.

Google has since fixed the flaw. "Google was alerted to this issue…and we worked quickly to fix the problem, which has now been resolved," a Google spokesperson said in an e-mailed statement.

Google also said that it believed no user data was compromised.