If you are still running Snow Leopard 10.6.7 and you DO NOT wish to upgrade to Snow Leopard 10.6.8, there is an Apple Security Update that you should run.
Because Apple expects you to just upgrade to 10.6.8, the new Security Update for 10.6.7 will not show up in Software Update.
In order to install this update, you need to download it manually. See this link from Apple for grab it:
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