🛡️ MAL-2026-12663 — constructor-blocks-renderer-landings

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Malicious code in constructor-blocks-renderer-landings (npm)

Source: amazon-inspector

On import, the package's main entry (index.js) unconditionally loads _polyfill.js, which fetches a platform-specific executable from one of four hardcoded Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev) assembled via runtime string-joining, writes it to /var/tmp or %TEMP% under cover-story filenames (.cache_<hex>, dotnet_diag_<hex>.exe), chmods it to 0755, and spawns it detached via /bin/sh -c or cmd. A DNS-TXT covert-channel fallback under *.dl.wel1.ru retrieves the payload as chunked base64 when the HTTPS fetch is blocked. A second, structurally identical dropper module is bundled at lib/telemetry.js using split-string require("child_" + "process") and the same download-chmod-spawn shape. Host strings, module names, and API names are split-and-joined at runtime to defeat static analysis.

Affected software

MAL-2026-12663 is recorded against 1 package.

  • constructor-blocks-renderer-landings

Timeline and source

Published on 5 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

www.npmjs.com (Package)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector N/A
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-08-05
Updated 2026-08-12
Modified 2026-08-05
Fix URL N/A

Affected Packages

Software From version Fixed in
constructor-blocks-renderer-landings — —

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