GreyMagic identified a total of nine vulnerabilities ranging from minor - a Web site operator being able to tell what keys a user is pressing in the Google search field - to serious - the scripting vulnerability.
The flaws were all patched by Google's automatic update to the toolbar, released on Wednesday, meaning that many Google Toolbar users should already be protected against the holes, GreyMagic said.
GreyMagic found the vulnerabilities in version 1.1.58 of the toolbar. Google is already distributing versions 1.1.59 and 1.1.60, which should fix the problems.
Among the less serious flaws found is the search bar keylogging described above, enabling the "Page Rank" and "Category" features that could reveal user information, clearing the toolbar's history or even uninstalling the application.
More seriously, by using a specific Uniform Resource Locator (URL), attackers could reroute searches through their own Web sites, allowing them to log information about users, the security group said.
By using other URLs containing scripts, an attacker can read files on the affected PC or execute scripts in the same security context that Web pages are viewed.
Users can check to see what version of the Google Toolbar they are running by clicking on the Google logo in the Toolbar and selecting "About Google Toolbar".
The Google Toolbar can be downloaded from http://toolbar.google.com