A day after the Obama administration proclaimed significant progress in its effort to spare troubled homeowners from foreclosure, an oversight panel on Friday sharply criticized the program and declared it would leave millions of Americans vulnerable to losing their homes.

In a report mild in language but pointed in substance, the Congressional Oversight Panel  a watchdog created last year to keep tabs on taxpayer bailout funds  said the administration’s program would, “in the best case,” prevent “fewer than half of the predicted foreclosures.”

The report rebuked the administration for failing to shape a program that addressed the most significant engines of the foreclosure crisis  soaring joblessness and exotic mortgages with low introductory interest rates that give way to sharply higher payments over the next three years. Many of those mortgages are too large to qualify for modification under the administration’s plan. People who lose their jobs often lack enough income to qualify for relief.

The administration’s plan appears “targeted at the housing crisis as it existed six months ago, rather than as it exists now,” asserted the oversight panel in its report. “The panel urges Treasury to reconsider the scope, scalability and permanence of the programs designed to minimize the economic impact of foreclosures and consider whether new programs or program enhancements could be adopted.”