MAL-2026-12522 Malicious code in capacity-capacity-core (npm)

Malicious package Published
Package
capacity-capacity-core
Registry
npm

What is MAL-2026-12522?

MAL-2026-12522 is a malicious package in capacity-capacity-core, published on 5 Aug 2026.

Official description

On require of the package's main entry, adapter.js downloads a platform-specific binary from one of three string-split-obfuscated Cloudflare Workers hosts (oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev), with a DNS TXT base64 fallback via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched bytes are written to /tmp or %TEMP% under a disguised name (.cache<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmod 0755, and detach-spawned via /bin/sh -c 'fp &' or cmd.exe /c start. A mtime marker at /tmp/.analytics_state throttles re-execution. Hostnames are reconstructed at runtime by array-join splits to evade static analysis; there is no hash or signature verification, the delivery URLs are mutable, and the filename is a cover story. Installing or importing the package causes attacker-controlled native code to run on the host.

What should I do about MAL-2026-12522?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

Sources

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