Which versions of code-tool-langfuse are malicious?

The following npm versions of code-tool-langfuse are flagged malicious: 0.1.0, 0.1.1, 0.1.2, 0.1.4, 0.1.7. Treat any of these as compromised.

How do I remediate code-tool-langfuse if I installed it?

Remove code-tool-langfuse 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.

I already installed code-tool-langfuse — how do I know if it already compromised me?

If code-tool-langfuse 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.

Is code-tool-langfuse part of a known attack campaign?

Yes — code-tool-langfuse is associated with the IN-MAL-2026-003377, IN-MAL-2026-003347, IN-MAL-2026-003332, IN-MAL-2026-003356, IN-MAL-2026-003344 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find code-tool-langfuse across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for code-tool-langfuse (5 malicious versions).

Malicious package

code-tool-langfusenpm

Advisory published May 20, 2026Updated May 26, 2026

code-tool-langfuse is a confirmed malicious npm package (MAL-2026-4532) that executes malicious code on install (malicious versions 0.1.0, 0.1.1, 0.1.2…). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in code-tool-langfuse (npm)

MAL-2026-4532

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall code-tool-langfuse

What this malware does

The package installs a Claude Code Stop hook and patches OpenCode plugin code so that every future AI session's user prompts, assistant responses, tool calls, and tool results are POSTed over plain HTTP to http://120.46.221.227:3000 — a bare-IP Langfuse instance controlled by the publisher. The destination URL and a live Langfuse public/secret key pair (pk-lf-da0c90a7-..., sk-lf-0269b85d-bfdc-442c-bfa3-e737954e3315) are hardcoded as defaults in bin/cli.js and in three setup scripts (scripts/langfuse-setup.mjs, scripts/opencode-langfuse-setup.mjs, scripts/langfuse-check.mjs). Setup persists these values into ~/.claude/settings.json, ~/.bashrc / ~/.zshrc, and the Windows User environment, and overwrites ~/.config/opencode/node_modules/opencode-plugin-langfuse/dist/index.js with an inlined patched module — establishing the relay across every future shell session and AI tool invocation. Because the secret key is bundled, any installer who runs the package becomes a writer to the publisher's Langfuse project, which simultaneously stores every other installer's uploaded transcripts; this is a cross-installer data-leak channel, not just author self-harm. Additionally, scripts/langfuse-setup.mjs downloads https://gitcode.com/user-attachments/files/8187690/<id>.zip via PowerShell Invoke-WebRequest, expands it into ~/.claude/hooks/, and registers the extracted Python file as a persistent Claude Stop hook with no version pin or hash verification — a mutable third-party attachment URL whose contents can be swapped at any time and would then run on every Claude Code session end. Installer transcripts routinely contain source code, pasted secrets, and file contents, so the silent default destination materially harms users who install this tool.

Malicious versions

5 flagged

0.1.00.1.10.1.20.1.40.1.7

Indicators of compromise (SHA-256)

13591fd81486fc2001b5c998ff87badefcb81f4c396aa43675a7280a6fed23cf

492f61b6a412e95db386b94c011565ec6fc2d231874f29f73c7ae6a327c422f1

5dab07364db88cf7f0051205ec0e4b538c78acd354d1aca4b97b40f2ac8a6e72

ad7940af7ae350155bcb08678c05996e1c0a62db4f195087be4a7d02d681597f

f6ca21a1b6d0b0aa67813438af32c2a53a5a4081464bb551e84593bcea8505eb

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for code-tool-langfuse (5 malicious versions).
If you installed it — respond
Remove code-tool-langfuse 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 code-tool-langfuse 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

No. code-tool-langfuse on npm has been identified as a malicious package (versions 0.1.0, 0.1.1, 0.1.2, 0.1.4, 0.1.7 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-003377IN-MAL-2026-003347IN-MAL-2026-003332IN-MAL-2026-003356IN-MAL-2026-003344

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks code-tool-langfuse-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.

Malware detection Runtime egress monitoring

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