Which versions of fulcrum-sessions are malicious?

The following npm versions of fulcrum-sessions are flagged malicious: 1.0.1, 1.1.0. Treat any of these as compromised.

How do I remediate fulcrum-sessions if I installed it?

fulcrum-sessions 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.

I already installed fulcrum-sessions — how do I know if it already compromised me?

If fulcrum-sessions 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 fulcrum-sessions part of a known attack campaign?

Yes — fulcrum-sessions is associated with the IN-MAL-2026-003464, IN-MAL-2026-003460 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 fulcrum-sessions across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for fulcrum-sessions (2 malicious versions).

Malicious package

fulcrum-sessionsnpm

Advisory published May 20, 2026Updated May 26, 2026

fulcrum-sessions is a confirmed malicious npm package (MAL-2026-4568) that steals credentials and exfiltrates sensitive data (malicious versions 1.0.1, 1.1.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in fulcrum-sessions (npm)

MAL-2026-4568

Immediate action

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

npm uninstall fulcrum-sessions

What this malware does

src/config.js hardcodes a live Telegram bot token (bot id 8656735452) and a default groupId (-1003974755050) pointing at a chat owned by the package author. getConfig() falls back to these defaults when the installer has not set TELEGRAM_BOT_TOKEN or edited ~/.fulcrum-sessions/config.json. The package's purpose is to bridge a Claude Code session to Telegram, so following the README quick-start (npm install -g fulcrum-sessions && fulcrum-sessions setup && fulcrum-sessions start) without first overriding the defaults causes every session message, voice transcript, photo, and document handled by the proxy to be polled from and POSTed to api.telegram.org as the author's bot — landing the installer's Claude Code conversation contents in the author's Telegram group. Nothing in the code enforces configuration before the daemon begins polling/sending. Additionally, the embedded bot token is a live third-party credential distributed to every installer, allowing anyone who reads the tarball to act as that bot against Telegram (read group updates, send messages). A separately-shipped Unsplash access key is author-self-harm only and not a basis for the verdict.

Malicious versions

2 flagged

1.0.11.1.0

Indicators of compromise (SHA-256)

ac82cf36a305545f8a74253f02cf75a7916409575e42abf67ba42d8ef1f26c58

f3971399e0fb1bd6c61f5306557512ed22dc0605747526b600b08626a50eb31e

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for fulcrum-sessions (2 malicious versions).
If you installed it — respond
fulcrum-sessions 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 fulcrum-sessions 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. fulcrum-sessions on npm has been identified as a malicious package (versions 1.0.1, 1.1.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-003464IN-MAL-2026-003460

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks fulcrum-sessions-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database