MAL-2026-6190

See a problem?
Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/mjs-eslint-helper/MAL-2026-6190.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-6190
Published
2026-06-19T03:59:02Z
Modified
2026-06-19T05:31:47.277827880Z
Summary
Malicious code in mjs-eslint-helper (npm)
Details

-= Per source details. Do not edit below this line.=-

Source: amazon-inspector (3320fa37492448acdf24a86f8a8735a3fc4d3b329ad156e299a8089df39e2f28)

The package decodes base64 string literals via Buffer.from(..., 'base64').toString() and pipes the resulting content into execSync('bash...') and execSync('zsh...') invocations in index.js (lines 9, 101, 117, 194, 195). This is the canonical fingerprint of an install-time/import-time dropper: an obfuscated payload is decoded and executed through a shell interpreter, giving the publisher arbitrary code execution on any machine that installs or requires this package. The package name impersonates the eslint helper namespace, consistent with a typosquat lure delivering an active payload. No legitimate eslint helper requires shelling out to bash/zsh from a base64-decoded blob.

Database specific 
{
    "malicious-packages-origins": [
        {
            "modified_time": "2026-06-19T03:59:02Z",
            "import_time": "2026-06-19T05:16:48.243232251Z",
            "versions": [
                "4.0.1"
            ],
            "source": "amazon-inspector",
            "id": "IN-MAL-2026-007042",
            "sha256": "3320fa37492448acdf24a86f8a8735a3fc4d3b329ad156e299a8089df39e2f28"
        }
    ]
}
References
Credits

Affected packages

npm / mjs-eslint-helper

Package

Name
mjs-eslint-helper
View open source insights on deps.dev
Purl
pkg:npm/mjs-eslint-helper

Affected ranges

Affected versions

4.*
4.0.1

Database specific

cwes 
[
    {
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code",
        "cweId": "CWE-506"
    }
]
indicators 
{
    "package_integrity": [
        {
            "filename": "mjs-eslint-helper-4.0.1.tgz",
            "hashes": {
                "sha512_sri": "sha512-edCO7/y1kXGlW1cS6ll4KSAcGEQj0drS37h9r6B5eM/fSiQErQm1VYt3r0G54LyvEwLNC6RXi2iEE7nxjfesZw==",
                "sha1": "6eff8f994efdcaa4d16613da7fee14bfdb677b7e"
            }
        }
    ],
    "evidence_files": [
        {
            "tlsh": "83e166a901162135d6f1f7f8e7560416f79ed2137202cb4276ac4ac92f77528e1d2eec",
            "path": "index.js",
            "sha256": "e15d42c5fa856a6b729a9bf44094c58d67694984c628e29250f613d10c98c851"
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/mjs-eslint-helper/MAL-2026-6190.json"