  Vacuum stability in the Standard Model is problematic as the Higgs quartic
self-coupling runs negative at a renormalization scale of about $10^{10}$ GeV.
We consider a non-supersymmetric SO(10) grand unification model for which gauge
coupling unification is made possible through an intermediate scale gauge
group, $G_{\text{int}}=\text{SU}(3)_C\otimes \text{SU}(2)_L\otimes
\text{SU}(2)_R \otimes \text{U}(1)_{B-L}$. $G_{\text{int}}$ is broken by the
vacuum expectation value of a 126 of SO(10) which not only provides for
neutrino masses through the seesaw mechanism but also preserves a discrete
$\mathbb{Z}_2$ that can account for the stability of a dark matter candidate,
here taken to be the Standard Model singlet component of a bosonic 16. We show
that in addition to these features the model insures the positivity of the
Higgs quartic coupling through its interactions to the dark matter multiplet
and 126. We also show that the Higgs mass squared runs negative triggering
electroweak symmetry breaking. Thus, the vacuum stability is achieved along
with radiative electroweak symmetry breaking and captures two more important
elements of supersymmetric models without low-energy supersymmetry. The
conditions for perturbativity of quartic couplings and for radiative
electroweak symmetry breaking lead to tight upper and lower limits on the dark
matter mass, respectively, and this dark matter mass region (1.35-2 TeV) can be
probed in future direct detection experiments.
