Cosa Intersects up to 1.7% U3O8 Within Interval of 5.0 m of 0.55% U3O8 at Murphy Lake North Joint Venture with Denison Mines

Vancouver, British Columbia, May 26 2026 – Cosa Resources Corp. (TSX-V: COSA) (OTCQB: COSAF) (FSE: SSKU) (“Cosa” or the “Company”) is pleased to report that chemical assays confirm previously-announced radioactive intersections include up to 1.7% U₃O₈ within a broader interval of 5.0 metres of 0.55% U₃O₈ at the Company’s Murphy Lake North (“MLN”) project. Muphy Lake North is a joint venture (the “Joint Venture”) between Cosa and Denison Mines Corp. (“Denison”) (TSX: DML) (NYSE American: DNN) and is located three kilometres east of IsoEnergy’s Hurricane deposit, in the eastern Athabasca Basin, Saskatchewan. Cosa is the project operator and holds a 70% interest with Denison holding a 30% interest.