---
id: "MAL-2026-18447"
kind: "package"
aliases: ["MAL-2026-18447"]
title: "Malicious code in zystcdemo (npm)"
severity: "critical"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "zystcdemo", "fixed": [], "affected": "= 1.0.0", "ecosystem": "npm"}]
ecosystems: ["npm"]
tags: ["malicious", "package"]
not_affected_if: []
published_at: "2026-10-29T07:22:48+00:00"
first_seen_at: "2026-11-02T06:21:27+00:00"
updated_at: "2026-11-02T06:23:10+00:00"
sources: [{"source": "osv-malicious", "url": "https://osv.dev/vulnerability/MAL-2026-18447", "first_seen_at": "2026-11-02T06:21:27+00:00"}]
---

# Malicious code in zystcdemo (npm)

## Affected

- npm:zystcdemo affected = 1.0.0 fixed ?

## Timeline

- 2026-11-02T06:21:27+00:00 osv-malicious https://osv.dev/vulnerability/MAL-2026-18447

## From the sources

zystcdemo presents itself as a simple date formatting utility and runs its postinstall payload on npm install with `node postinstall.js`. The payload collects the `whoami` result, hostname, platform, and current time, then sends them in a POST request to `https://srctest.zystcc.cn/collect`; npm account `zyst` published it on 2026-10-29 (UTC).

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