# MAL-2026-5734: Malicious code in node-denv (npm)


- **Type:** Malicious package
- **Package:** `node-denv` (npm)
- **Published:** 13 Jun 2026
- **Also known as:** GHSA-8mfj-gmpr-xqqr

## What is MAL-2026-5734?

MAL-2026-5734 is a malicious package in node-denv, published on 13 Jun 2026. 

### Official description

node-denv presents itself as a pino-compatible logging middleware (index.js exports `module.exports.pino = middleware` and mimics pino's option shape including DEFAULT_LEVELS, formatters.bindings, redact, and customLevels). When a consumer instantiates the middleware, the package spawns a detached `node lib/caller.js` child process. lib/caller.js performs an HTTPS GET against https://jsonkeeper.com/b/EXSIF, reads the `.cookie` field from the JSON response, and passes it to `new Function.constructor("require", s)` invoked with the real `require` — granting the remotely-fetched JavaScript full Node.js capabilities (filesystem, network, child_process, env). The fetch is retried up to 5 times. A second jsonkeeper.com payload URL (https://jsonkeeper.com/b/ZK45J) is base64-encoded as `DEV_API_KEY` in lib/const.js as a fallback C2. jsonkeeper.com is an anonymous mutable JSON paste host — the attacker can change the executed payload at any time without republishing the package. The pino impersonation lures developers searching for the popular logger into installing this package, at which point any normal use triggers remote code execution on the installer's machine.

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-2026-5734?

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-2026-5734 is a malicious package: node-denv (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-2026-5734/ (Markdown: https://insights.sbomify.com/MAL-2026-5734/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5734

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5734/
Summaries are generated and may contain mistakes; the official description above is the record.