Apple has issued a security update for Safari for Mac today, addressing a couple of issues with WebKit.
Impact: Visiting a maliciously crafted website may lead to an unexpected application termination or arbitrary code execution
Description: Multiple memory corruption issues existed in WebKit. These issues were addressed through improved memory handling.
Impact: Inconsistent user interface may prevent users from discerning a phishing attack
Description: A user interface inconsistency existed in Safari that allowed an attacker to misrepresent the URL. This issue was addressed through improved user interface consistency checks.
You should be able to snag the update by checking the "updates" section in the Mac App Store now.
Thanks to Jack for the tip!