MAL-2026-12559

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/checkout-desktop-pay-widget/MAL-2026-12559.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-12559
Published
2026-08-05T14:12:55Z
Modified
2026-08-05T14:35:23.258793858Z
Summary
Malicious code in checkout-desktop-pay-widget (npm)
Details

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

Source: amazon-inspector (6d9f6914ba98b5cf6aa04dd51fb0ef5a1f454a0cb87409ea43482afd6b99b38d)

On require('checkout-desktop-pay-widget'), index.js loads shim.js which selects a platform-specific asset, downloads an opaque native binary from one of four runtime-assembled Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev / cf100-416.workers.dev variants), writes it to /tmp or %TEMP% under decoy names (.cache<hex> on POSIX, dotnetdiag<hex>.exe on Windows), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe. Destination hostnames are split into fragments and joined at runtime to evade static string scanning. A DNS-TXT fallback channel resolves TXT records under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, concatenates chunks, base64-decodes the result to executable bytes, and runs them — a covert payload-retrieval channel that bypasses HTTP egress controls. No signature or hash verification is performed. Function names (bootstrap/telemetry, DISABLETELEMETRY,.analyticsstate lock file) present a benign cover story that conflicts with the fetch-write-chmod-exec chain. Package name mimics a checkout/payment widget but the shipped code implements a full-host remote code execution dropper.

Database specific 
{
    "malicious-packages-origins": [
        {
            "sha256": "6d9f6914ba98b5cf6aa04dd51fb0ef5a1f454a0cb87409ea43482afd6b99b38d",
            "id": "IN-MAL-2026-015211",
            "modified_time": "2026-08-05T14:12:55Z",
            "import_time": "2026-08-05T14:20:13.25726382Z",
            "source": "amazon-inspector",
            "versions": [
                "35.6.3"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / checkout-desktop-pay-widget

Package

Name
checkout-desktop-pay-widget
View open source insights on deps.dev
Purl
pkg:npm/checkout-desktop-pay-widget

Affected ranges

Affected versions

35.*
35.6.3

Database specific

indicators 
{
    "evidence_files": [
        {
            "sha256": "a8bc2c59f6ecd92ff19654b6f97b6b68130c4f02b0266dcf4db906720ecf9a33",
            "path": "_shim.js",
            "tlsh": "a7b1a69a167a70188bb0a7e4c71b4415f66bf66337808294f79ca5985f72124c3b2ffc"
        }
    ],
    "package_integrity": [
        {
            "hashes": {
                "sha512_sri": "sha512-Jrt7Fcu3NYPl+y9DCR8iT+hZ4o01N70hWzwPfYJVdiU8keM44fucOLRn7HmjTHIbZ2Vkw5ITSZ7vJgw+qSfSLw==",
                "sha1": "5aed91c8d466fbc42e262e1ddecff8fd41fccf87"
            },
            "filename": "checkout-desktop-pay-widget-35.6.3.tgz"
        }
    ]
}
cwes 
[
    {
        "name": "Embedded Malicious Code",
        "description": "The product contains code that appears to be malicious in nature.",
        "cweId": "CWE-506"
    }
]
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/checkout-desktop-pay-widget/MAL-2026-12559.json"