Cosa Intersects 1.7% U3O8 Within 5.0 m of 0.55% U3O8 at Murphy Lake North JV with Denison Mines

Vancouver, British Columbia--(Newsfile Corp. - May 26, 2026) - Cosa Resources Corp. (TSXV: 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% U 3 O 8 within a broader interval of 5.0 metres of 0.55% U 3 O 8 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.

Highlights Uranium mineralization confirmed in three holes featuring a best intercept in MLN26-013 of 5.0 metres averaging 0.55% U 3 O 8 including 0.5 metres 1.7% U 3 O 8 along the Cyclone trend The 5.0 metre uranium intersection in MLN26-013 also contains 4.1% nickel and 1.7% cobalt, consistent with multiple polymetallic eastern Athabasca uranium deposits including Cigar Lake, Key Lake, and Hurricane Uranium mineralization is shallow at 265 metres depth and remains open along strike for 600 metres to the west and 600 metres to the east Joint Venture is in final stages of planning its largest drill program to date to follow up these results Keith Bodnarchuk, President and CEO, commented: " This is a significant result for Cosa, with the assays confirming that Cyclone hosts uranium mineralization comparable to discovery intersections from multiple Athabasca uranium deposits. The Cyclone trend is an extensive corridor of strong structure and alteration that now features uranium mineralization that is open along strike for 600 metres in both directions. We expect to update the market in the coming days with plans for our largest drill program to date as a company.

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