@langgraphjs/toolkitnpm
Advisory published Updated
@langgraphjs/toolkit is a confirmed malicious npm package (MAL-2026-2509) that steals credentials and exfiltrates sensitive data (malicious versions 1.2.10, 1.2.11, 1.2.12…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in @langgraphjs/toolkit (npm)
What this malware does
Package collects and sends sensitive system info to a hardcoded server. The package masquerades as a LangGraph JS utility but contains a malicious postinstall script.
The package's scripts/postinstall.js executes on npm install and collects installer-side identity and cloud/git metadata, then POSTs it as JSON to a hardcoded Google Cloud Run endpoint at npm-package-logger-228835561205.europe-west1.run.app. Collected data includes: git-configured emails from ~/.gitconfig,.git/config, and up to 15 reflog HEAD author emails; GitHub CLI login and email from hosts.yml; SSH public key comments from ~/.ssh/*.pub; GCP project and account identifiers from ~/.config/gcloud/properties; AWS profile names from ~/.aws/config; /etc/resolv.conf search domain; os.hostname(), os.userInfo().username, os.platform(), and cwd; plus parent project package.json details. The package name @langgraphjs/toolkit impersonates the legitimate @langchain/langgraph ecosystem (and the langgraphjs.guide domain referenced in the script), and declares @langchain/langgraph and @langchain/core as dependencies to appear legitimate. Its advertised main entry dist/index.js is not shipped in the tarball — only src/ and scripts/ — so the only code that actually runs on install is the harvester. Behavior is framed as anonymous telemetry/compatibility diagnostics, but the systematic enumeration of ~/.ssh, ~/.aws, ~/.config/gcloud, ~/.gitconfig, and git reflog is credential-adjacent identity theft, not telemetry.
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for @langgraphjs/toolkit (4 malicious versions).
If you installed it — respond
@langgraphjs/toolkit is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If @langgraphjs/toolkit was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- SafeDep · finder
Detect & block this
O3 blocks @langgraphjs/toolkit-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.