MAL-2026-13078 Malicious code in boxy-rspack-optimize-sharing-runtime (npm)

The package's index.js unconditionally requires./bridge on module load. bridge.js selects a platform-specific payload path (linux_x64, linux_arm64, darwin, win32.exe), downloads bytes from a rotating list of *.workers.dev hosts whose hostnames are reconstructed by array-joining string fragments (e.g. ['oob-worker.cf100','-416.worke','rs','.de','v'].join('')), with a DNS-TXT fallback that reassembles a base64 payload from chunked TXT records under *.wel1.ru (sdk./ext./pkg./net.dl.wel1.ru). The fetched bytes are written to /var/tmp/.cache<hex> or %TEMP%\dotnet_diag<hex>.exe, chmod 0755, then spawned detached via /bin/sh -c '<path> &' or cmd.exe /c start /b. A second file lib/telemetry.js ships the same drop-and-exec primitives (base64 chunk reassembly, string-concatenated fs['chmod'+'Sync'], /bin/sh spawn) framed as an APM SDK, though it is not on the reachable graph from index.js. Filenames such as.cache_/.analytics_state/dotnet_diag_ and a DISABLE_TELEMETRY env check are cover framing; the endpoint reconstruction and DNS-TXT smuggling are not legitimate telemetry patterns. Any require/import of this package results in remote code execution on the host.