MAL-2026-12662

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/constructor-blocks-mailings/MAL-2026-12662.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-12662
Published
2026-08-05T13:58:20Z
Modified
2026-08-05T14:36:13.321505638Z
Summary
Malicious code in constructor-blocks-mailings (npm)
Details

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

Source: amazon-inspector (5124a2b9217dc772621cdedf3938c8ed063ede4daa0fdd82c2e11b9df85403fb)

On require() of the package, index.js loads adapter.js which selects a platform-specific endpoint, downloads an opaque binary from obfuscated Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev) with a DNS-TXT base64 fallback channel via numbered subdomains under *.dl.wel1.ru, writes it to /tmp or %TEMP% under disguised names (.cache<hex>, dotnetdiag<hex>.exe, analytics_state), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start. Destination hostnames are assembled from split string fragments (e.g. "oob-worker.c"+"f100-416.workers.dev") to evade static analysis. The fetched bytes are opaque with no hash or signature verification. The combination of load-time execution, obfuscated rotated C2, DNS-TXT covert delivery channel, cover-story file naming, and unverified binary execution matches a hostile install/load-time dropper.

Database specific 
{
    "malicious-packages-origins": [
        {
            "source": "amazon-inspector",
            "import_time": "2026-08-05T14:20:03.392939552Z",
            "versions": [
                "35.5.7"
            ],
            "id": "IN-MAL-2026-015113",
            "modified_time": "2026-08-05T13:58:20Z",
            "sha256": "5124a2b9217dc772621cdedf3938c8ed063ede4daa0fdd82c2e11b9df85403fb"
        }
    ]
}
References
Credits

Affected packages

npm / constructor-blocks-mailings

Package

Name
constructor-blocks-mailings
View open source insights on deps.dev
Purl
pkg:npm/constructor-blocks-mailings

Affected ranges

Affected versions

35.*
35.5.7

Database specific

source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/constructor-blocks-mailings/MAL-2026-12662.json"
indicators 
{
    "package_integrity": [
        {
            "hashes": {
                "sha1": "13f90bb165b8b4c2e3660578c7c7d4827dd3ad22",
                "sha512_sri": "sha512-ZGpz0frb+wy/EIqAZuqEk2808mU/GPhHfzTd7bskt507kuhhzzU7HAUg0MXb2kK63yuD5vPC9H0KItcaCJVoog=="
            },
            "filename": "constructor-blocks-mailings-35.5.7.tgz"
        }
    ],
    "evidence_files": [
        {
            "tlsh": "a7a1739a166a701c4bb0ebf496174415f65ae6633681c288fa5c68981fb35248372efc",
            "path": "_adapter.js",
            "sha256": "cead6f8f90bfbf1df0ea8ae189951f8f6d160623b5e4868520087bd9918850d3"
        }
    ]
}
cwes 
[
    {
        "cweId": "CWE-506",
        "name": "Embedded Malicious Code",
        "description": "The product contains code that appears to be malicious in nature."
    }
]