Summary: We study the stability of the \(\text{O}(N)\) fixed point in three dimensions under perturbations of the cubic type. We address this problem in the three cases \(N= 2, 3, 4\) by using finite-size scaling techniques and high-precision Monte Carlo simulations. It is well known that there is a critical value \(2< N_c< 4\) below which the \(\text{O}(N)\) fixed point is stable and above which the cubic fixed point becomes the stable one. Whilst we cannot exclude that \(N_c< 3\), as recently claimed, our analysis strongly suggests that \(N_c\) coincides with 3.