The Treasury Department could exhaust its cash by late fall if a new federal debt ceiling plan isn't put in place, according to a Congressional Budget Office report.
The government can no longer borrow normally after March 15 under a measure enacted last year to suspend the debt limit. It could borrow temporarily after the deadline through so-called extraordinary measures but would run out of money in October or November, the CBO said.
The agency stressed that the timeline is far from certain. However, it sets up a congressional vote on raising the debt ceiling before U.S. cash is exhausted and the government defaults on its obligations.
Debt limit deadlines have often proved contentious in the past. Congressional Republicans have used debt deadlines as leverage for spending cuts during President Barack Obama's tenure.
Read MoreSame as it ever was: Congress is still broken
The most recent debt ceiling was $17.2 trillion and debt accumulated since last year's suspension brings the total to $18.1 trillion, the CBO said.
The Treasury Department did not immediately respond to CNBC's request for comment on the report.