The report criticizes the TSA for having inadequate plans to keep itself running in a terror attack, disaster or other emergency.
Such planning "has not been a priority for TSA nor have adequate resources been available," Inspector General Richard Skinner wrote.
The TSA disputed the predictions, saying it could continue to operate during an emergency.
In a statement Thursday, the TSA called its contingency plans effective and said they got high marks during a recent test of how the agency would respond to an attack.
In a July letter to Skinner, the TSA said it has made contingency plans a "high priority" and is rewriting the plan to address shortcomings.
The TSA's potential problems suggest a fundamental flaw with national security, said Clark Kent Ervin, Skinner's predecessor. "If an agency that's designed to help the rest of the country recover can't itself recover from an attack, how helpful can it be to the rest of the country?"
Federal agencies must have plans enabling them to function for 30 days after an emergency.
The TSA's plan is "cumbersome" because it includes too many activities and people instead of focusing on priorities, Skinner's report said.
Some of the actions called for in TSA's current emergency plan include answering routine complaints and collecting customer feedback.
The TSA doesn't prioritize its plans and never completed a review of them, the report says.