  The LHAASO collaboration has reported their observation of very high energy
photons ($E^{max}_\gamma \simeq 18$ TeV) from the gamma-ray burst GRB221009A.
The sterile neutrino that involves both mixing and transition magnetic moment
may be a viable explanation for these high energy photon events. However, we
demonstrate that such a solution is strongly disfavored by the cosmic microwave
background (CMB) and Big Bang nucleosynthesis (BBN) in the standard cosmology.
