Bitcoin wallet bug let rogue servers steal funds when users tried to speed up payments

A critical security flaw was discovered in a Bitcoin wallet, enabling malicious servers to steal funds from users. The attack vector involved attackers replacing legitimate Bitcoin transactions with fake ones and then waiting for users to attempt to speed up their payments by approving higher fees. When users approved these higher fees, they unknowingly authorized the fraudulent transactions, leading to the loss of their Bitcoin. The article confirms that at least one person lost Bitcoin due to this vulnerability. Developers have since identified and patched the flaw, mitigating the risk for other users.