  LHAASO collaboration detected photons with energy above 10 TeV from the most
recent gamma-ray burst (GRB), GRB221009A. Given the redshift of this event,
$z\sim 0.15$, photons of such energy are expected to interact with the diffuse
extragalactic background light (EBL) well before reaching Earth. In this paper
we provide a novel neutrino-related explanation of the most energetic 18 TeV
event reported by LHAASO. We find that the minimal viable scenario involves
both mixing and transition magnetic moment portal between light and sterile
neutrinos. The production of sterile neutrinos occurs efficiently via mixing
while the transition magnetic moment portal governs the decay rate in the
parameter space where tree-level decays via mixing to non-photon final states
are suppressed. Our explanation of this event, while being consistent with the
terrestrial constraints, points to the non-standard cosmology.
