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Description
Self-bound dark matter subhalos are predicted to populate galactic halos in great abundance in the Cold Dark Matter (CDM) scenario. These substructures can leave observable imprints in strong gravitational lensing and have shown the ability to account for flux-ratio and image position anomalies in the multiple lensed images. In this paper, we utilize the dark matter subhalos to address the image positional anomalies of the two radio quads of HS 0810+2554 observed by the Very Long Baseline Interferometry. We model the lens using an elliptical power-law macromodel supplemented by a population of CDM subhalos from numerical simulations and perform a dual-source reconstruction to fit all eight radio images simultaneously. We find that subhalos below $10^{6}M_\odot$ induce astrometric shifts smaller than the measurement uncertainties, whereas more massive subhalos naturally generate the required milliarcsecond perturbations without significantly altering the global lens configuration. Including CDM subhalos improves the fit from $\chi=7.77$ for the pure macromodel to $\chi=1.27$. Our results show that the position anomalies of HS~0810+2554 can be explained within the CDM framework and do not by themselves necessarily require non-standard dark matter scenarios like fuzzy dark matter or angular complexity in the main lens. Instead, they provide a sharp and testable manifestation of the subhalo population predicted by CDM.