# MAL-2026-5845: Malicious code in prettier_v1 (npm)


- **Type:** Malicious package
- **Package:** `prettier_v1` (npm)
- **Published:** 15 Jun 2026
- **Also known as:** GHSA-q835-5j9v-22qg

## What is MAL-2026-5845?

MAL-2026-5845 is a malicious package in prettier_v1, published on 15 Jun 2026. 

### Official description

Package name 'prettier_v1' closely resembles the widely-used 'prettier' formatter package, a classic typosquat naming pattern. The file lib/mirror.js contains a Buffer.from(..., 'base64').toString('utf8') decode primitive at line 16, which is commonly used to obscure embedded payloads. Tracing of the decoded content and its downstream use (whether it is passed to eval/exec, written to disk, or executed) was not completed, so the actual installer-side impact has not been confirmed. The combination of a typosquat-shaped name plus a base64 decode in a file named 'mirror.js' warrants human review before this package is allowed into installer environments.

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-2026-5845?

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-2026-5845 is a malicious package: prettier_v1 (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-2026-5845/ (Markdown: https://insights.sbomify.com/MAL-2026-5845/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5845

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5845/
Summaries are generated and may contain mistakes; the official description above is the record.