# MAL-2026-12857: Malicious code in bigops-watermark (npm)


- **Type:** Malicious package
- **Package:** `bigops-watermark` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-pvr5-5pcp-mh66

## What is MAL-2026-12857?

MAL-2026-12857 is a malicious package in bigops-watermark, published on 5 Aug 2026. 

### Official description

On require() of the package, index.js unconditionally loads _support.js, whose init() runs at module load. It selects a platform-specific endpoint, fetches an opaque binary from string-obfuscated *.workers.dev hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev) with DNS-TXT base64 fallbacks resolving to sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, writes the payload to /tmp or %TEMP% under a disguised name (.cache_<hex> or dotnet_diag_<hex>.exe), chmods it 0755, and spawns it detached via /bin/sh -c or cmd. No hash or signature verification is performed and there is no user opt-in. Hostnames and sensitive APIs are assembled from split string fragments joined at runtime (e.g. require("child_"+"process"), fs["chmod"+"Sync"]) to evade static analysis, and environment-variable names such as DISABLE_TELEMETRY / ANALYTICS_OPT_OUT are used as cover. A duplicate dropper implementation is also shipped in lib/telemetry.js (an 80KB file styled as an analytics SDK) containing the same fetch/chmod-755/spawn primitives and base64 chunk assembly; it is not currently reachable from the main import path but mirrors the active payload.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-12857?

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-2026-12857 is a malicious package: bigops-watermark (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-2026-12857/ (Markdown: https://insights.sbomify.com/MAL-2026-12857/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12857

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12857/
Summaries are generated and may contain mistakes; the official description above is the record.