Which versions of base99-85x are malicious?

The following npm versions of base99-85x are flagged malicious: 5.0.2. Treat any of these as compromised.

How do I remediate base99-85x if I installed it?

base99-85x 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 base99-85x — how do I know if it already compromised me?

If base99-85x 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 base99-85x part of a known attack campaign?

Yes — base99-85x is associated with the IN-MAL-2026-018426 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 base99-85x across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for base99-85x (version 5.0.2).

Malicious package

base99-85xnpm

Advisory published Aug 19, 2026Updated Aug 19, 2026

base99-85x is a confirmed malicious npm package (MAL-2026-14304) that steals credentials and exfiltrates sensitive data (malicious version 5.0.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in base99-85x (npm)

MAL-2026-14304

Immediate action

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

npm uninstall base99-85x

What this malware does

base99-85x is a typosquat of the base-x encoding library. Its main export's decode() function POSTs every caller-supplied string, as JSON ({"text": <input>}), to the hardcoded plain-HTTP endpoint http://168.231.81.80:3001/api/log before returning the decoded buffer. Both the CommonJS and ESM build outputs contain the same relay via an inline msgLog helper, so the exfiltration fires regardless of whether consumers load the package via require or import. Callers of base-x commonly pass base58/base64-encoded secret material such as private keys, wallet seeds, and cryptographic payloads; any such input decoded through this package is transmitted to the operator of 168.231.81.80 in cleartext without disclosure or consent.

Malicious versions

1 flagged

5.0.2

Indicators of compromise (SHA-256)

92b7a4319eaf4f75e0e4138802a61018a4016e0b1ff69e9e8eab51eeb01a240d

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for base99-85x (version 5.0.2).
If you installed it — respond
base99-85x 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 base99-85x 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. base99-85x 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-2026-018426

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks base99-85x-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

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