MAL-2026-13758 Malicious code in bs58-11 (npm)

Package bs58-11 is published under a name that resembles the popular bs58 module. Its README self-identifies as bs58 and instructs npm i --save bs58, while package.json declares the name as bs58-11. The tarball contains only a two-line wrapper (index.cjs) that requires base65-11x — a name resembling the legitimate base-x package — and immediately invokes its default export at module load. The wrapper itself contains no exfiltration, credential access, install-time fetch-and-execute, silent-relay, or backdoor code. Any behavior beyond base-x-style alphabet decoding depends on the content of the base65-11x dependency, which is not part of this tarball.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.