Which versions of @mastra/express are malicious?

The following npm versions of @mastra/express are flagged malicious: 1.3.31. Treat any of these as compromised.

How do I remediate @mastra/express if I installed it?

@mastra/express 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 @mastra/express — how do I know if it already compromised me?

If @mastra/express 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 @mastra/express part of a known attack campaign?

Yes — @mastra/express is associated with the GHSA-r6w3-xpw9-p9g6, IN-MAL-2026-009553 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 @mastra/express 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 @mastra/express (version 1.3.31). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @mastra/express across your stack and pipelines.

Malicious package

@mastra/expressnpm

@mastra/express is a confirmed malicious npm package (MAL-2026-6022) that steals credentials and exfiltrates sensitive data (malicious version 1.3.31). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in @mastra/express (npm)

MAL-2026-6022

Immediate action

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

npm uninstall @mastra/express

What this malware does

The package's bundled distribution files (dist/index.cjs and dist/index.js) contain a Buffer.from(..., 'base64').toString('utf-8') decode pattern. This pattern by itself is benign and extremely common in JavaScript bundles — used for inline data URIs, JWT segment parsing, encoded SVG/PNG assets, configuration constants, and similar legitimate purposes. No corroborating evidence of credential theft, exfiltration, dropper behavior, lifecycle-script abuse, or hardcoded attacker infrastructure was observed. The match is on a single keyword pattern in a bundled main module with no traced harmful execution path.

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

1.3.31

Indicators of compromise (SHA-256)

c7375ba72b0d9da5bf4d20ab526cb654b97310e39965bea22eb5d3d0557961d4

9cd00df32d6d56cd3d4996965ed13e18c1da3a9b0007392b4fc14da1a8fcbb46

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @mastra/express (version 1.3.31). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @mastra/express across your stack and pipelines.
If you installed it — respond
@mastra/express 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 @mastra/express 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 @mastra/express 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. @mastra/express on npm has been identified as a malicious package (version 1.3.31 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-r6w3-xpw9-p9g6IN-MAL-2026-009553

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks @mastra/express-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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