MS10-021 addresses eight different Windows vulnerabilities. “Five of them, CVE-2010-0234 through CVE-2010-0238, stem from an obscure bit of Windows registry functionality called “registry links”. A quick search in MSDN reveals this description: “REG_LINK: Specifies a Unicode symbolic link. Used internally. Applications do not use this type”. Clear as mud, right? Registry links are similar to symbolic links in NTFS. They create a special type of registry key that, when navigated to, redirects the user to another location of the registry. Examining the affected platforms for each case, it’s evident that the majority of these issues were found and fixed in Vista, due to the extra security work required by SDL. None of the issues affect Windows 7 or Windows Server 2008. Users who’ve moved beyond Windows XP are better off than others,” notes Microsoft.