MAL-2026-13521

    Dashboard / Malicious Package / MAL-2026-13521

    MAL-2026-13521

    Published: 7 Aug 2026Last Modified: 7 Aug 2026

    Summary: Malicious code in @rbxst/services (npm)

    Details: Source: amazon-inspector (f8e349df2092cb3672698c00cefa5268881f21a60d1f71394c9e223b40d086d2) scripts/postinstall.js runs at npm install time. On Windows it downloads a ZIP archive from https://files.catbox.moe/rp8idk.zip (anonymous file-hosting service, mutable content), uses PowerShell Expand-Archive to unpack it to a randomized temp directory, then spawns a bundled pythonw.exe against exec_.py with detached:true, stdio:'ignore', windowsHide:true, and child.unref(), so the fetched payload runs hidden and outlives the npm process. The script exits silently on non-Windows platforms. The package advertises roblox-ts service type utilities and has no legitimate need to fetch and execute a Python interpreter from an anonymous file host. This matches the alternate-runtime dropper pattern from known-bad infrastructure: an opaque remote payload executes on the installer's machine with the installer's privileges.

    References: https://www.npmjs.com/package/@rbxst/services/v/1.0.756

    Affected packages

    Package

    Name: @rbxst/services

    Purl: pkg:npm/%40rbxst/services

    Affected ranges

    Type: N/A

    Events:

    Introduced- None
    Fixed -None

    Affected versions

    1.0.756
    MAL-2026-13521 | CVE-DB