# MAL-2026-13722: Malicious code in fsbrowse (npm)


- **Type:** Malicious package
- **Package:** `fsbrowse` (npm)
- **Published:** 10 Aug 2026
- **Also known as:** GHSA-pvvh-h7rh-2c7g

## What is MAL-2026-13722?

MAL-2026-13722 is a malicious package in fsbrowse, published on 10 Aug 2026. 

### Official description

The package's main entry file (index.js) contains a legitimate Express file-server module followed by a unicode-escape-obfuscated IIFE appended after whitespace padding. When the module is loaded (via `require('fsbrowse')`, `server.js`, or the `fsbrowse` bin), the trailing code queries Ethereum RPC endpoints (eth.blockscout.com, 1rpc.io/eth, eth.drpc.org, ethereum-rpc.publicnode.com, eth-mainnet.public.blastapi.io) for the latest outgoing transaction of hardcoded address 0xa322E5f3D311D3080e6f0121063e9aDC2490Ef1a, decodes two IPv4 addresses from the transaction `to` field, then fetches XOR-encrypted payloads from those hosts over http://<ip>:443/0x/cls and executes the decrypted Node code via `eval` and via `spawn('node', ['-e',...], { detached: true, stdio: 'ignore' })`. Core module names (`http`, `https`, `zlib`, `url`, `child_process`), method names (`spawn`, `eth_getBlockByNumber`, `eth_getTransactionCount`), destination URLs, the Ethereum address, and XOR keys are all written as `\u00XX` escape sequences to hide the behavior from casual review. This is the EtherHiding technique: on-chain resolution of C2 IPs to defeat static blocklists, followed by fetch-and-execute of attacker-supplied code with the installer's privileges at import time.

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-2026-13722?

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-2026-13722 is a malicious package: fsbrowse (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-2026-13722/ (Markdown: https://insights.sbomify.com/MAL-2026-13722/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-13722

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-13722/
Summaries are generated and may contain mistakes; the official description above is the record.