Microsoft today issued a raft of software updates to plug at least 19 security holes in its various Windows operating systems and other software, 15 of which earned the company’s most dire “critical” rating. This month’s batch of patches fix some fairly dangerous flaws. Redmond labels a security flaw “critical” if attackers could use it to seize control over a vulnerable system without any help from the victim. What’s more, a dozen of the flaws earned the highest rating on Microsoft’s “exploitability index,” which is the software maker’s best estimation of the likelihood that criminals will soon develop reliable ways to exploit them to break into Windows-based machines. Patches are available for Windows 2000, XP, Vista, Windows Server 2003 and Windows Server 2008. Microsoft said none of the vulnerabilities affect Windows 7, its newest operating system. Windows users can download the updates from Windows Update or via Automatic Updates Many