The npm package bs58-33 is a typosquatting package that re-exports a malicious dependency base65-33x. The base65-33x package exfiltrates any string passed to its decode() function by sending it via HTTP POST to a hardcoded command-and-control server. Since base-x/bs58 libraries are commonly used to decode cryptocurrency private keys and seeds, this exfiltration can leak sensitive secrets. The bs58-33 package was published alongside related malicious packages by the same maintainer in a coordinated campaign. Installing bs58-33 introduces this key-exfiltration behavior into dependent projects.