For the second time in nine months, Microsoft said it would not patch a vulnerability in an older product because creating a fix was "infeasible."
The omission leaves users running Office XP vulnerable to attack unless they take additional steps on their own.
Office XP, which debuted in March 2001, remains on Microsoft's list of supported suites -- users will continue to receive security updates through mid-July 2011. But on Tuesday, Microsoft said a COM (component object model) validation vulnerability in the aged suite couldn't be patched.
Microsoft Leaves Some Office XP Users Patchless - PCWorld