The origin of magnetic fields in the Universe is an open problem in cosmology. Seed magnetic fields produced at early times may have survived up to the present day close to their original form, virtually undisturbed by processes of structure formation, consequently providing a window into the primeval Universe. Intergalactic magnetic fields (IGMFs) are poorly constrained. Electromagnetic cascades initiated by high-energy gamma rays in the intergalactic medium can be used to derive lower bounds on the strength of IGMFs, since their charged component is sensitive to the intervening fields. It is possible to probe IGMFs by combining spectral, temporal, and angular information from distant sources of high-energy gamma rays such as blazars. Nevertheless, there is an ongoing debate about a possible quenching effect of plasma instabilities, which can hinder the development of the cascades. In this talk I will review the status of gamma-ray studies of IGMFs. I will then present a novel multimessenger strategy to probe IGMFs using combined gamma-ray and neutrino observations from flaring objects. Finally, I will present the first constraints on the coherence length of IGMFs based on observations of TXS 0506+056, the first cosmic neutrino source.