fs-commons

GHSA-72c4-xhr8-m5j8

Malicious code in fs-commons (npm)

Details

**Severity:** Critical

**Affected versions:** `= 1.0.1`

## Source: amazon-inspector (f7e82e98343807c39ea786017de4d2a7455815424155ca2a856333d895c8a48b)
The package presents itself as a filesystem/data-helper library, but its exported getTransactions()/load_transaction_data() functions are a two-file dynamic-code loader. index.js hides the identifiers 'Function', 'require', 'process', 'Buffer', and 'setTimeout' behind a split-string array and obtains the Function constructor indirectly via globalThis.constructor.constructor, defeating static review. At call time it reads the sibling file models.js, which is disguised as an array of product-record objects but whose `mark` fields are base64 ciphertext. loadConfig()/processData() sort the records by id, concatenate every `mark`, apply a per-count Caesar shift, base64-decode the result, and pass the resulting source to the Function constructor with Buffer, require, and process injected, then invoke it. Any consumer that requires fs-commons and calls getTransactions() executes attacker-supplied code with full Node privileges on the host process. The obfuscation, the indirect Function-constructor acquisition, and the disguising of the payload as product metadata in a sibling file have no legitimate purpose for a data-helper library and are the fingerprint of a supply-chain remote-code-execution package.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/1cde083711b79b90c1fc554005660fcd3bfc30dc/osv/malicious/npm/fs-commons/MAL-2026-17301.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/1cde083711b79b90c1fc554005660fcd3bfc30dc/osv/malicious/npm/fs-commons/MAL-2026-17301.json
- https://www.npmjs.com/package/fs-commons/v/1.0.1
- https://github.com/advisories/GHSA-72c4-xhr8-m5j8

Compromised versions (1)

= 1.0.1

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.