Which versions of base65-13x are malicious?

The following npm versions of base65-13x are flagged malicious: 5.0.2. Treat any of these as compromised.

How do I remediate base65-13x if I installed it?

base65-13x is a typosquat — you almost certainly intended a legitimately-named package. Remove base65-13x, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

I already installed base65-13x — how do I know if it already compromised me?

If base65-13x 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.

Is base65-13x part of a known attack campaign?

Yes — base65-13x is associated with the IN-MAL-2026-017378, GHSA-fp83-xcpx-v3qm 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 base65-13x across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for base65-13x (version 5.0.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging base65-13x across your stack and pipelines.

Malicious package

base65-13xnpm

base65-13x is a confirmed malicious npm package (MAL-2026-13747) that typosquats a legitimate package to trick installs (malicious version 5.0.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in base65-13x (npm)

MAL-2026-13747

Immediate action

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

npm uninstall base65-13x

What this malware does

[email protected] impersonates cryptocoinjs/base-x, reusing its README, homepage, and API surface, but the exported decode(string) function in both src/esm/index.js (line 114) and src/cjs/index.cjs (line 116) contains a ~123KB VM-style obfuscated payload using rotated identifiers (vmR, vmr_92f1a9, vmw_4ee781) built via Object.defineProperty. The blob contains multiple references to the Function constructor and fetch, indicating dynamic code construction and outbound network I/O. Genuine base-x is roughly 50 lines of pure arithmetic with no obfuscation and no network activity. Any consumer invoking decode() on this package executes the packed VM, which dynamically constructs code with fetch capability. The destination hosts and constructed code are concealed by the obfuscation and are not statically visible.

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

1 flagged

5.0.2

Indicators of compromise (SHA-256)

59226f2c38efcc1dd5de6423edfc866125564cd726915307d7a05ca5b5f13529

8f16b7879f3a0b67bc7621645bf52c742af231c6e4156550ff4393f0167936ad

Detection & response playbook

Typosquat

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for base65-13x (version 5.0.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging base65-13x across your stack and pipelines.
If you installed it — respond
base65-13x is a typosquat — you almost certainly intended a legitimately-named package. Remove base65-13x, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If base65-13x 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 base65-13x 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

No. base65-13x on npm has been identified as a malicious package (version 5.0.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-017378GHSA-fp83-xcpx-v3qm

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks base65-13x-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

Explore

All malware advisories How O3 detects malware Vulnerability database