We report the results of a search for exotic decays of a Higgs boson with m_\mathrm{h}=125~\mathrm{GeV} to a pair of new light bosons, , where one of the light bosons decays to a pair of muons and the other one decays to a pair of b quarks. Such signatures are predicted in a number of well motivated extensions of the standard model, including the next-to-minimal supersymmetry and generic two Higgs doublet models with an additional scalar singlet. A data sample corresponding to an integrated luminosity of 19.7~\mathrm{fb}^{-1} recorded with the CMS detector in 2012 is exploited in final states where no statistically significant excess is observed with respect to the standard model backgrounds for different hypotheses above 25 GeV and below . Upper limits are set on and on the branching ratio itself with former ranging between 4 to 12~\mathrm{fb}, depending on the values. The limit on the branching ratio is for the entire mass range.