MAL-2026-17481

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/css-light-dark-polyfill/MAL-2026-17481.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-17481
Published
2026-10-04T23:14:43Z
Modified
2026-10-04T23:30:05Z
Summary
Malicious code in css-light-dark-polyfill (npm)
Details

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

Source: amazon-inspector (856c154d7855924568c88181f172f46e84aac202bd6cb29974eb2ffaa3ec3ea7)

The package presents itself as a trivial CSS polyfill (index.js exports an empty object) but ships thunderboltRegistry.js, which on load runs a self-invoking IIFE that collects host identifiers (os.hostname, node version, platform, pid) and the output of local shell commands (id, whoami, uname -a, ifconfig/ip addr, /etc/hosts via child_process.execSync) and POSTs each result via fetch() to the hardcoded endpoint https://dxpoc.gt.tc/callback.php/. The payload self-labels as 'beacon=rce-poc'. The package also exports factories under the names of internal Wix Thunderbolt build registries (thunderboltRegistry, siteAssetsRegistry, documentManagementRegistry, editorRegistry, etc.), and a bundled registry-manifest.min.json maps those names to parastorage.com URLs — a dependency-confusion shape targeting Wix-like build systems that resolve these internal registry module names. Installing or loading this package causes host reconnaissance data to be exfiltrated to an attacker-controlled domain unrelated to any CSS polyfill functionality.

Database specific 
{
    "malicious-packages-origins":  [
        {
            "id":  "IN-MAL-2026-020889",
            "import_time":  "2026-10-04T23:16:30.610450244Z",
            "modified_time":  "2026-10-04T23:14:43Z",
            "sha256":  "856c154d7855924568c88181f172f46e84aac202bd6cb29974eb2ffaa3ec3ea7",
            "source":  "amazon-inspector",
            "versions":  [
                "1.0.0"
            ]
        }
    ]
}
References
Credits

Affected packages

npm / css-light-dark-polyfill

Package

Name
css-light-dark-polyfill
View open source insights on deps.dev
Purl
pkg:npm/css-light-dark-polyfill

Affected ranges

Affected versions

1.*
1.0.0

Database specific

cwes 
[
    {
        "cweId":  "CWE-506",
        "description":  "The product contains code that appears to be malicious in nature.",
        "name":  "Embedded Malicious Code"
    }
]
indicators 
{
    "evidence_files":  [
        {
            "path":  "thunderboltRegistry.js",
            "sha256":  "162b586676df1ff1f68e8fa553b7053c4ee80317c786d39cd9a46e058410d01a",
            "tlsh":  "b37144a5b99df02066c33438cb7f4049b4bbd6672d6caee0744999b01f7985c01be6f8"
        }
    ],
    "package_integrity":  [
        {
            "filename":  "css-light-dark-polyfill-1.0.0.tgz",
            "hashes":  {
                "sha1":  "b1bc0b2218421d571d3d9f36bf0c4fe46f6797f0",
                "sha512_sri":  "sha512-0HY1YYoiHUBIuwO/R9OLMQjzE5cJ2vLTpfeeyB++4qby8WDSNezzVpdf0gGp5XCZFJhQ6CSBTWcQIsMvcrv2Yg=="
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/css-light-dark-polyfill/MAL-2026-17481.json"