* Canadian dollar at C$1.2792, or 78.17 U.S. cents
* Loonie hit weakest since Nov. 21 at C$1.2808
* Bond prices higher across the yield curve
* 10-yr yield hits lowest since Aug. 30 at 1.832 pct
TORONTO, Nov 28 (Reuters) - The Canadian dollar weakened to a one-week low against its U.S. counterpart on Tuesday as oil prices fell, ahead of the release by the Bank of Canada of an assessment of vulnerabilities and risks in the country's financial system.
At 9:25 a.m. ET (1425 GMT), the Canadian dollar CAD=D4 was trading at C$1.2792 to the greenback, or 78.17 U.S. cents, down 0.2 percent.
The currency's strongest level of the session was C$1.2756, while it touched its weakest since Nov. 21 at C$1.2808.
The price of oil, one of Canada's major exports, fell on uncertainty over the outcome of a key Organization of the Petroleum Exporting Countries meeting this week. crude CLc1 prices fell 0.31 percent to $57.93 a barrel.
The Bank of Canada is due to release its semi-annual Financial System Review at 10:30 a.m. ET (1530 GMT).
Investors will peruse comments by Bank of Canada Governor Stephen Poloz for clues on the prospects for further interest rate hikes after weak retail sales data last week.
The central bank raised rates in July and September for the first time in seven years but has since turned more cautious on the outlook for the economy.
Canadian government bond prices were higher across the yield curve, with the two-year CA2YT=RR up 4 Canadian cents to yield 1.419 percent and the 10-year CA10YT=RR rising 38 Canadian cents to yield 1.843 percent.
The 10-year yield touched its lowest since Aug. 30 at 1.832 percent, while the gap between the 10-year yield and its U.S. equivalent widened by 3.9 basis points to a spread of -47.8 basis points.
Data will be released Friday on Canada's jobs for November and gross domestic product for the quarter.