Which versions of debug-fmt are malicious?

Every published version of debug-fmt on npm is considered malicious. Remove the package entirely.

How do I remediate debug-fmt if I installed it?

Remove debug-fmt from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

I already installed debug-fmt — how do I know if it already compromised me?

If debug-fmt 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 debug-fmt part of a known attack campaign?

Yes — debug-fmt is associated with the GHSA-hvhh-9q7c-6g8m 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 debug-fmt 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 debug-fmt (all published versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging debug-fmt across your stack and pipelines.

Malicious package

debug-fmtnpm

Malicious code in debug-fmt (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-566

Immediate action

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

npm uninstall debug-fmt

What this malware does

The package debug-fmt was found to contain malicious code.

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

all versions

Every published version of this package is considered malicious — remove it entirely.

Indicators of compromise (SHA-256)

1f7e76c50ec40bd53847463f61469ebfb4691c221c290d98fed82736214216cc

049bf4db6a598df3cc4db93a71b765670e9b94be0c835ae183fd91c13fe99d8b

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for debug-fmt (all published versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging debug-fmt across your stack and pipelines.
If you installed it — respond
Remove debug-fmt from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If debug-fmt 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 debug-fmt 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. debug-fmt on npm has been identified as a malicious package (all published versions flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-hvhh-9q7c-6g8m

References

github.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks debug-fmt-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