The 15,000 Malibus being recalled over fire concerns are 2013 models fitted with the optional power front seats. According to a statement from Chevrolet, the wiring harness in the seats could fray against seat frames, which could lead to a fire. The span of time where affected cars were built isn't entirely clear, but Chevy reports that there have been no reported injuries or crashes caused by the issue.
As for the remaining 44,000 models being recalled, it applies to 2014 Malibus, which have a defective defroster in the HVAC. Rather than causing fires like the seat issue, the defroster just might not work when called upon. While a minor issue, the ability to defog the windows is important for driver visibility.
The total distribution of affected models sees 57,605 cars being recalled in the US, 1,047 in Canada and 683 in Mexico. As of this writing, there's been no word from the National Highway Traffic Safety Administration.