Which versions of fontus are malicious?

The following PyPI versions of fontus are flagged malicious: 0.0.1, 0.0.2, 0.0.3. Treat any of these as compromised.

How do I remediate fontus if I installed it?

fontus 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 fontus — how do I know if it already compromised me?

If fontus 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 fontus part of a known attack campaign?

Yes — fontus is associated with the 2026-10-fontus 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 fontus across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for fontus (3 malicious versions).

Malicious package

fontusPyPI

Advisory published Oct 25, 2026Updated Oct 25, 2026

fontus is a confirmed malicious PyPI package (MAL-2026-18271) that steals credentials and exfiltrates sensitive data (malicious versions 0.0.1, 0.0.2, 0.0.3). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in fontus (PyPI)

MAL-2026-18271

Immediate action

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

pip uninstall fontus

What this malware does

The package most likely performs fingerprinting by exfiltrating basic information and available fonts, with no other functionality.

Category: PROBABLY_PENTEST - Packages looking like typical pentest packages, but also anything that looks like testing, exploring pre-prepared kits, research & co, with clearly low-harm possibilities.

Campaign: 2026-10-fontus

Reasons (based on the campaign):

The package contains code to exfiltrate basic data from the system, like IP or username. It has a limited risk.

Malicious versions

3 flagged

0.0.10.0.20.0.3

Indicators of compromise (SHA-256)

2a8fcff0fd4d827c6f174318ee41ea82eb2667c6d65349a01ca2215aa2f4dd5e

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for fontus (3 malicious versions).
If you installed it — respond
fontus 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 fontus 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. fontus on PyPI has been identified as a malicious package (versions 0.0.1, 0.0.2, 0.0.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

2026-10-fontus

References

bad-packages.kam193.eu

Credits

Kamil Mańkowski (kam193) · analyst

Detect & block this

O3 blocks fontus-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

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