LONDON—The cost of insuring Dubai's sovereign debt against default rose to its highest level since November as concerns resurfaced over the emirate's large debt.

According to CMA DataVision, Dubai's five-year credit-default-swap spread—a measure of credit risk—rose close to 0.5 percentage point to trade up at 6.32 percentage points in late trading Friday. These elevated levels indicated that Dubai is considered one of the riskiest sovereigns in the world behind only Argentina, Venezuela, Ukraine and Pakistan.

The...