Microsoft today said it will ship four security updates to customers next week that will include the final public fixes for flaws in Windows XP and Office 2003, both slated for retirement from security support on Tuesday.

Of the four updates, two were tagged "critical," Microsoft's most serious threat rating, and the other pair was marked "important," the next step down in the firm's four-part scoring system.

All four, however, were labeled in today's advance notification with the phrase "remote code execution," meaning that attackers could hijack an unpatched PC if they managed to exploit the vulnerabilities. Microsoft often downgrades remote code flaws to the important category when there are mitigating factors -- say, a requirement that users click through multiple warnings or deviate from a standard configuration -- that prevent easy exploitation.

One of the quartet will directly affect Windows XP -- all versions of Windows, actually, including the newest, Windows 8.1 -- while another will also impact the 13-year-old OS because it will patch all editions of Internet Explorer, including IE6, which faces retirement, too, and IE8, the most popular Microsoft browser for XP.

The small number of fixes for XP on the eve of its retirement didn't surprise Andrew Storms, director of DevOps at San Francisco-based security vendor CloudPassage.

"I think a lot of people have made much ado about nothing regarding the end of life for XP," said Storms in an interview conducted via instant messaging. "One of those being the hallucination that we would see a dump truck full of last-minute XP patches next week. It's not like Microsoft to sit on a bunch of known bugs for a long time and release them all on an arbitrary date. Take Pwn2Own for example: We almost never see a bunch of IE bugs get squashed the month before."