🛡️ MAL-2026-13746 — base65-12x

Malicious code in base65-12x (npm)

Source: amazon-inspector

The package name base65-12x typosquats the popular base-x base-encoding library and reuses base-x's repository as its homepage. Both the CJS entry (index.js around line 116) and the ESM entry (src/esm/index.js around line 114) append an approximately 123 KB top-level obfuscated block after a copy of the legitimate base-x source. The block installs a VM-style dispatcher on globalThis (registries named vmr_3f4688 and vmw_bf472f), manipulates Object.defineProperty and __proto__, and contains multiple fetch references, so a network-capable code path is wired up and runs unconditionally when a consumer requires or imports the package. A base-encoding library has no functional need for a large globalThis-poisoning obfuscated VM with network fetch at module top level; the payload is duplicated across both module systems so it fires for CJS and ESM consumers alike.

Source: ghsa-malware

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.