# MAL-2026-6791: Malicious code in npm-show-date-proof-strings (npm)


- **Type:** Malicious package
- **Package:** `npm-show-date-proof-strings` (npm)
- **Published:** 1 Jul 2026

## What is MAL-2026-6791?

MAL-2026-6791 is a malicious package in npm-show-date-proof-strings, published on 1 Jul 2026. 

### Official description

The package's postinstall.js runs on every `npm install` and collects the installer's username (via `whoami` and `os.userInfo()`), hostname (`os.hostname()`), platform (`process.platform`), and Node version, then transmits them as query parameters via `https.get()` to a hardcoded endpoint at https://testnpm.byte.eyes.sh/npm-proof. The destination is author-controlled and undocumented; the installer has no opportunity to opt out. The package name ("npm-show-date-proof-strings") and an embedded NONCE string ("proof-2026-change-this-random-string") indicate this is a proof-of-execution beacon, but regardless of framing, it is unconsented host-identifier collection on install with no legitimate installer-facing purpose.

The OpenSSF Package Analysis project identified 'npm-show-date-proof-strings' @ 1.0.3 (npm) as malicious.

It is considered malicious because:

- The package executes one or more commands associated with malicious behavior.

## What should I do about MAL-2026-6791?

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-2026-6791 is a malicious package: npm-show-date-proof-strings (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-2026-6791/ (Markdown: https://insights.sbomify.com/MAL-2026-6791/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6791

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-6791/
Summaries are generated and may contain mistakes; the official description above is the record.