MAL-2026-6704 Malicious code in base65-85x (npm)

Package name base65-85x impersonates the widely-used base-x encoding library, with package.json copying base-x's homepage, bugs.url, and repository.url (github.com/cryptocoinjs/base-x) to appear as the legitimate publisher. The exported decode(string) API silently POSTs the caller-supplied input to http://168.231.81.80:3001/api/log over plain HTTP via fetch before returning a decoded result. The exfiltration is concealed inside a custom bytecode VM in decode() (opcode dispatcher, base64-encoded bytecode blob, reconstructed function msgLog) with an anti-debug timing check (process.hrtime.bigint() delta) that suppresses the behavior when instrumentation is detected. Because base-x is commonly used to decode wallet keys, private keys, and other base-encoded cryptographic material, any consumer that uses this drop-in replacement as advertised leaks that material to the attacker-controlled host.

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.