CVE-2026-56744: Bsv-Blockchain @bsv/wallet-Toolbox

High severity, CVSS 8.7. EPSS: 0.3% chance of exploitation in the next 30 days.

`@bsv/wallet-toolbox` provides BRC-100 wallet signing and storage components, while `@bsv/wallet-toolbox-client` and `@bsv/wallet-toolbox-mobile` provide client-focused distributions for standard and mobile applications using wallet storage services. A vulnerability in these packages causes transactions created through a remote `StorageClient` to trust output locking scripts returned by the storage provider without verifying that they match the outputs requested by the caller. A malicious or compromised storage provider can substitute a recipient script or inject an additional output, causing the wallet to sign and broadcast a transaction that redirects funds while the application and user interface continue to display the intended recipient. Source and npm publication history indicate that stable versions `@bsv/wallet-toolbox` and `@bsv/wallet-toolbox-client` from 1.1.47 through 2.3.3, and `@bsv/wallet-toolbox-mobile` from its initial 1.3.21 release through 2.3.3, are affected. All three packages are patched in version 2.4.0. Applications unable to upgrade should avoid remote `StorageClient` providers, use local storage, or independently verify every transaction output’s locking script and value against the original request before signing

Affected products

• Bsv-Blockchain @bsv/wallet-Toolbox: from 1.1.47, before 2.4.0 (fixed in 2.4.0)
• Bsv-Blockchain @bsv/wallet-Toolbox-Client: from 1.1.47, before 2.4.0 (fixed in 2.4.0)
• Bsv-Blockchain @bsv/wallet-Toolbox-Mobile: from 1.3.21, before 2.4.0 (fixed in 2.4.0)

Published 2026-09-24. Last modified 2026-09-30.