  In order to accommodate the observed Higgs boson mass in the CMSSM, the stops
must either be very heavy or the mixing in the stop sector must be very large.
Lower stop masses, possibly more accessible at the LHC, still give the correct
Higgs mass only if the trilinear stop mixing parameter $|A_t|$ is in the
multi-TeV range. Recently it has been shown that such large stop mixing leads
to an unstable electroweak vacuum which spontaneously breaks charge or colour.
In this work we therefore go beyond the CMSSM and investigate the effects of
including baryon number violating operators $\lambda'' \bar{\bf U} \bar{\bf
D}\bar{\bf D}$ on the stop and Higgs sectors. We find that for $\lambda''
\simeq {\mathcal{O}}(0.3)$ light stop masses as low as 220 GeV are consistent
with the observed Higgs mass as well as flavour constraints while allowing for
a stable vacuum. The light stop in this scenario is often the lightest
supersymmetric particle. We furthermore discuss the importance of the one-loop
corrections involving R-parity violating couplings for a valid prediction of
the light stop masses.
