william-data-formatter-x (npm) · Malicious Code
Affects william-data-formatter-xSource GCVE Database
Malicious package : remove william-data-formatter-x and rotate any secrets on hosts that installed it.
Data as of 5 Aug 2026, 17:51 UTC
Malicious package
Published to npm · OSV MAL-2026-12501
What to do
Remove william-data-formatter-x from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| npmwilliam-data-formatter-x | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
The npm package 'william-data-formatter-x' version 1.0.0 contains malicious code that executes during installation on Windows systems. It runs a preinstall script that launches a hidden PowerShell window to download and execute an unverified binary from an anonymous file hosting service. This results in arbitrary attacker-controlled code execution on the host machine at install time.