npm

base65-13x @5.0.2

Vulnerability report · Last retrieved from osv.dev August 12, 2026 at 3:23 AM UTC

Malicious

OSV ID

MAL-2026-13747

Ecosystem

npm

Summary

base65-13x@5.0.2 impersonates cryptocoinjs/base-x, reusing its README, homepage, and API surface, but the exported decode(string) function in both src/esm/index.js (line 114) and src/cjs/index.cjs (line 116) contains a ~123KB VM-style obfuscated payload using rotated identifiers (vmR, vmr_92f1a9, vmw_4ee781) built via Object.defineProperty. The blob contains multiple references to the Function constructor and fetch, indicating dynamic code construction and outbound network I/O. Genuine base-x is roughly 50 lines of pure arithmetic with no obfuscation and no network activity. Any consumer invoking decode() on this package executes the packed VM, which dynamically constructs code with fetch capability. The destination hosts and constructed code are concealed by the obfuscation and are not statically visible.

Source: amazon-inspector (59226f2c38efcc1dd5de6423edfc866125564cd726915307d7a05ca5b5f13529)

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