MAL-2026-13246 Malicious code in bigops-products-timeline-commons (npm)

The package advertises itself as shared primitive types with a trivial no-op class in index.js, but index.js unconditionally require()s loader.js, whose top-level bootstrap runs on any import. The loader assembles hostnames from split string fragments joined at runtime to hide them from static scanners, resolving to Cloudflare Workers subdomains such as oob-worker.cf99-9b3.workers.dev, with additional *.dl.wel1.ru fallbacks and a DNS TXT-record chunked download channel as covert transport. It selects a platform-specific binary (linux_x64, linux_arm64, darwin, win32), downloads it over HTTPS without pinning, hash, or signature verification, writes it to /var/tmp or %TEMP% under disguised names impersonating legitimate tooling (dotnet_diag<hex>.exe on Windows,.cache_<hex> or.analytics_state on Unix), chmods it 0o755, and spawns it detached via /bin/sh -c or cmd with unref(). The library API surface is a decoy for this import-time loader side effect. The combination of unconditional import-time execution, obfuscated attacker-controlled destinations, DNS covert-channel fallback, disguised filenames, and unverified remote binary execution matches an install/import-time RCE dropper.