MAL-2026-12602 Malicious code in checkout-use-notifications (npm)
Malicious package
Published
MAL-2026-12602 is a malicious package: checkout-use-notifications (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-2026-12602/ (Markdown: https://insights.sbomify.com/MAL-2026-12602/index.md)
- Package
- checkout-use-notifications
- Registry
- npm
What is MAL-2026-12602?
MAL-2026-12602 is a malicious package in checkout-use-notifications, published on 5 Aug 2026.
Official description
On require of the package, index.js unconditionally loads shim.js, which fetches a platform-specific binary from obfuscated Cloudflare Workers hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev) with a DNS TXT-record fallback channel via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. Hostnames are assembled at runtime by joining split string fragments to evade static detection. The fetched payload is written to /tmp or %TEMP% under disguised names (.cache<rand>, dotnet_diag_<rand>.exe), chmod 0755 on Unix, and spawned detached via /bin/sh -c or cmd with stdio ignored. The DNS fallback base64-decodes numbered TXT chunks to reconstruct the payload when HTTPS fetches fail. An anti-re-run stamp gates repeated execution. The delivery infrastructure, string-split hostname obfuscation, disguised on-disk filenames, and DNS covert channel are canonical malicious dropper fingerprints.
What should I do about MAL-2026-12602?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.