48degC is 120degF.
It's warmer than I would normally expect, though it depends on:
a) cooler used
b) fan profile
c) case cooling
d) ambient room temperature
e) how OLD the CPU cooler is (may need thermal paste replaced)
The main issue would be if you're constantly going over 80degC as that can wear out the CPU. If that's an issue, or if the fan is just a bit noisy then consider going to PCPARTPICKER and look for something like the CM Hyper 212 EVO, Cryorig H7 or similar.
And use the MOTHERBOARD fan software (motherboard site) to optimize the fan profile.