# MAL-2026-15625: Malicious code in evilpostinstall (npm)


- **Type:** Malicious package
- **Package:** `evilpostinstall` (npm)
- **Published:** 31 Aug 2026

## What is MAL-2026-15625?

MAL-2026-15625 is a malicious package in evilpostinstall, published on 31 Aug 2026. 

### Official description

The package's postinstall lifecycle hook pipes the output of `env` through `nc` to a host reconstructed at install time from the package version string via `cut -b 2-4` and `cut -b 5-`. For version 4127000.0.1 the destination decodes to 127.0.0.1:888; the sibling artifact evilpostinstall-192.168.1.100.tgz uses the same slicing scheme to target 192.168.1.100. On `npm install`, the full installer environment - including any CI secrets, tokens, and API keys present in environment variables - is transmitted to the reconstructed host over TCP port 888. package.json also declares a self-referencing dependency `evilpostinstall: ^4192168.1.100`, whose version field encodes a second destination IP under the same scheme, causing npm to resolve and install an additional package instance whose own postinstall repeats the exfiltration against that address. The destination is deliberately hidden from static scanners by being reconstructed from the version field rather than written as an IP literal, and no source files are shipped - the manifest itself is the payload.

The OpenSSF Package Analysis project identified 'evilpostinstall' @ 4127000.0.1 (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-2026-15625?

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-2026-15625 is a malicious package: evilpostinstall (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-2026-15625/ (Markdown: https://insights.sbomify.com/MAL-2026-15625/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-15625

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-15625/
Summaries are generated and may contain mistakes; the official description above is the record.