The upgrade of the CMS muon system for the High Luminosity LHC

The muon system of the CMS experiment is expected to upgrade all of its subdetectors for the Phase-2 of the Large Hadron Collider (LHC) that will begin in 2029. The upgrade plans for drift tubes (DTs), cathode strip chambers (CSCs) and resistive place chambers (RPCs) include a new electronics for better performance in high background rate conditions and to sustain the large radiation dose delivered by the high-luminosity LHC (HL-LHC). Two new RPC stations will also be installed to complement CSCs in the forward region $1.8<\mathrm{\mid }\eta \mathrm{\mid }<2.4$, while three stations of triple-GEM (gas electron multiplier) detectors will complement CSCs in the region $1.5<\mathrm{\mid }\eta \mathrm{\mid }<2.4$ and extend the CMS muon system coverage in the very forward pseudorapidity region up to $\mathrm{\mid }\eta \mathrm{\mid }=2.8$. We present the goals and status of the CMS muon system upgrade including the performance of the early Phase-2 upgrades demonstrated in Run 3 with proton-proton collisions, the performance validation of the new detectors in test beams and the mass production status of the new stations.