MAL-2026-12550 Malicious code in checkout-context (npm)
Malicious package
Published
MAL-2026-12550 is a malicious package: checkout-context (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-2026-12550/ (Markdown: https://insights.sbomify.com/MAL-2026-12550/index.md)
- Package
- checkout-context
- Registry
- npm
What is MAL-2026-12550?
MAL-2026-12550 is a malicious package in checkout-context, published on 5 Aug 2026.
Official description
On require, helpers.js reassembles hostnames via array split-and-join to hide the destinations (oob-worker.cf*.workers.dev and *.dl.wel1.ru subdomains including sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru), downloads a platform-specific binary via https.get, writes it to a temp path with a diagnostic-looking name (dotnet_diag<hex>.exe on Windows,.cache_<hex> on Unix), chmods it 0755, and spawns it detached via /bin/sh or cmd. A persistence flag file named.analytics_state is written by helper _l. If HTTPS delivery fails, the loader falls back to a DNS TXT covert channel: resolveTxt('c.'+domain) gives a chunk count, then i.'+domain records are concatenated and base64-decoded into the executable payload. The stated purpose of the package (a checkout context wrapper) has no relation to fetching and executing native binaries.
What should I do about MAL-2026-12550?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.