Which versions of base65-12x are malicious?

The following npm versions of base65-12x are flagged malicious: 5.0.2. Treat any of these as compromised.

How do I remediate base65-12x if I installed it?

base65-12x is a typosquat — you almost certainly intended a legitimately-named package. Remove base65-12x, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.

I already installed base65-12x — how do I know if it already compromised me?

If base65-12x 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 base65-12x part of a known attack campaign?

Yes — base65-12x is associated with the IN-MAL-2026-017380, GHSA-c4w7-m3hx-xx75 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 base65-12x 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 base65-12x (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 base65-12x across your stack and pipelines.

Malicious package

base65-12xnpm

base65-12x is a confirmed malicious npm package (MAL-2026-13746) 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 base65-12x (npm)

MAL-2026-13746

Immediate action

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

npm uninstall base65-12x

What this malware does

The package name base65-12x typosquats the popular base-x base-encoding library and reuses base-x's repository as its homepage. Both the CJS entry (index.js around line 116) and the ESM entry (src/esm/index.js around line 114) append an approximately 123 KB top-level obfuscated block after a copy of the legitimate base-x source. The block installs a VM-style dispatcher on globalThis (registries named vmr_3f4688 and vmw_bf472f), manipulates Object.defineProperty and proto, and contains multiple fetch references, so a network-capable code path is wired up and runs unconditionally when a consumer requires or imports the package. A base-encoding library has no functional need for a large globalThis-poisoning obfuscated VM with network fetch at module top level; the payload is duplicated across both module systems so it fires for CJS and ESM consumers alike.

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)

79b553d84d7f4dc5347840ddb97f16738eed2e52ac9757b48d2cb31ba1af7122

4891fcf0d0e6192d9be14faf68411bd475129a1245b5c863a9daaa6f66e66166

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 base65-12x (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 base65-12x across your stack and pipelines.
If you installed it — respond
base65-12x is a typosquat — you almost certainly intended a legitimately-named package. Remove base65-12x, 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 base65-12x 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 base65-12x 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. base65-12x 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-2026-017380GHSA-c4w7-m3hx-xx75

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks base65-12x-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