# MAL-2026-12537: Malicious code in cbp-exchange-government-cbp-exchange-government-core (npm)


- **Type:** Malicious package
- **Package:** `cbp-exchange-government-cbp-exchange-government-core` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-12537?

MAL-2026-12537 is a malicious package in cbp-exchange-government-cbp-exchange-government-core, published on 5 Aug 2026. 

### Official description

index.js unconditionally requires./_loader on module load. _loader.js assembles three Cloudflare Workers hostnames via split-array `.join("")` obfuscation (oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev), fetches an opaque platform-specific native binary via `https.get`, writes it to /var/tmp or %TEMP% under a decoy name (e.g. dotnet_diag_<hex>.exe,.cache_<hex>), chmods it 0755, and spawns it detached via `cp.spawn("/bin/sh", ["-c", fp + " &"], {detached:true}).unref()` (or `spawn("cmd",...)` on Windows). A secondary DNS-TXT covert channel under sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru reconstructs a base64-encoded payload from numbered TXT records (`c.<domain>` count + `<i>.<domain>` chunks) when the HTTPS fetch fails. The binary is unpinned, unhashed, and served from anonymous Workers subdomains — arbitrary attacker-controlled code executes on any host that installs or requires the package. lib/telemetry.js contains parallel dropper primitives (split-string `require("child_" + "process")`, `fs["chmod" + "Sync"]`, `cp.spawn("/bin/sh",...)`) staged but not currently reachable from the main entry.

## What should I do about MAL-2026-12537?

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

## Fix prompt for AI coding agents

```text
MAL-2026-12537 is a malicious package: cbp-exchange-government-cbp-exchange-government-core (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-2026-12537/ (Markdown: https://insights.sbomify.com/MAL-2026-12537/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12537

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12537/
Summaries are generated and may contain mistakes; the official description above is the record.