MAL-2026-12592 Malicious code in checkout-storage-service (npm)
Malicious package
Published
MAL-2026-12592 is a malicious package: checkout-storage-service (npm). Every version was published to cause harm.
Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.
Reference: https://insights.sbomify.com/MAL-2026-12592/ (Markdown: https://insights.sbomify.com/MAL-2026-12592/index.md)
- Package
- checkout-storage-service
- Registry
- npm
What is MAL-2026-12592?
MAL-2026-12592 is a malicious package in checkout-storage-service, published on 5 Aug 2026.
Official description
On require of checkout-storage-service, helpers.js selects a platform-specific endpoint and downloads bytes over HTTPS from a rotating list of Cloudflare Workers subdomains (oob-worker.cf103-070.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev), with a DNS-TXT covert-channel fallback under sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched payload is written to /tmp/.cache<hex> on Unix or TEMP\dotnet_diag_<hex>.exe on Windows, chmod 0755, and spawned detached via /bin/sh -c or cmd.exe. Host strings are assembled from split arrays via.join('') to evade static analysis, execution is throttled by a TTL flag file and DO_NOT_TRACK-style env checks styled as opt-out telemetry, and stderr logging is silenced by a no-op sink. The destination hosts are anonymous Cloudflare Workers unrelated to the package publisher, the payload is opaque, and the staged filenames (hidden dotfile in /tmp, dotnet_diag masquerade on Windows) are intended to blend into normal system paths.
What should I do about MAL-2026-12592?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.