A vulnerability in Nomic’s custom forwarding mechanism allowed an attacker to double-spend nBTC and generate false cross-chain vouchers that were sent to Osmosis. These vouchers resulted in unbacked nBTC entering Osmosis and becoming part of Alloyed BTC’s backing. Osmosis and IBC were not compromised. After detecting the issue, Osmosis froze Nomic and Alloyed BTC inflows and outflows and coordinated an emergency upgrade with validators that froze 22.65 BTC in the attacker’s address