  We investigate the current status of the light neutralino dark matter
scenario within the minimal supersymmetric standard model (MSSM) taking into
account latest results from the LHC. A discussion of the relevant constraints,
in particular from the dark matter relic abundance, leads us to a manageable
simplified model defined by a subset of MSSM parameters. Within this simplified
model we reinterpret a recent search for electroweak supersymmetric particle
production based on a signature including multi-taus plus missing transverse
momentum performed by the ATLAS collaboration. In this way we derive stringent
constraints on the light neutralino parameter space. In combination with
further experimental information from the LHC, such as dark matter searches in
the monojet channel and constraints on invisible Higgs decays, we obtain a
lower bound on the lightest neutralino mass of about 24 GeV. This limit is
stronger than any current limit set by underground direct dark matter searches
or indirect detection experiments. With a mild improvement of the sensitivity
of the multi-tau search, light neutralino dark matter can be fully tested up to
about 30 GeV.
