The bsv-rs crate's Shamir backup recovery mechanism accepted shares with an x coordinate of 0, allowing an attacker to supply a crafted share that directly determines the recovered private key. This flaw existed since the crate's first release (0.2.0) and was fixed in versions 0.8.7 and 0.9.0-beta.7.0. The vulnerability allows an attacker to substitute the recovered private key if the application recovers a Shamir backup from shares it did not originally produce.