  An unidentified line at energy around 3.5 keV was detected in the spectra of
dark matter-dominated objects. Recent work of Dessert et al. [1812.06976] used
30 Msec of XMM-Newton blank-sky observations to constrain the admissible line
flux, challenging its dark matter decay origin. We demonstrate that these
bounds are overestimated by more than an order of magnitude due to improper
background modeling. Therefore the dark matter interpretation of the 3.5 keV
signal remains viable.
