MAL-2026-12766 Malicious code in devplatform-spa-plugin-error-boundary (npm)

The package's main index.js unconditionally requires./ext, which runs at load time and fetches a per-platform binary over HTTPS from string-concatenation-obfuscated Cloudflare Workers hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf99-9b3.workers.dev). If HTTPS fails, ext.js falls back to a DNS TXT covert channel under *.dl.wel1.ru (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru), querying c.<domain> for a chunk count then 0.<domain>, 1.<domain>,… and base64-decoding the concatenation into a binary. The fetched bytes are written to a randomly-named file in the temp directory (masquerading as.cache<hex>, dotnet_diag<hex>.exe, analytics_state), chmod'd 0755, and spawned detached via /bin/sh -c or cmd /c start /b. There is no version pinning, hash verification, or publisher-owned CDN, and the package's stated purpose (an SPA error-boundary component) has no legitimate reason to fetch and execute a native binary. Endpoint hostnames are assembled from split array literals at runtime to defeat static string scanning. Loading this package causes arbitrary attacker-controlled code to run on the installer's host.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.