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 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.

Malicious versions

1 flagged

5.0.2

Indicators of compromise (SHA-256)

79b553d84d7f4dc5347840ddb97f16738eed2e52ac9757b48d2cb31ba1af7122

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-2026-017380

References

npmjs.com

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

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