Which versions of @mastra/agent-browser are malicious?

The following npm versions of @mastra/agent-browser are flagged malicious: 0.3.2. Treat any of these as compromised.

How do I remediate @mastra/agent-browser if I installed it?

@mastra/agent-browser 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/agent-browser — how do I know if it already compromised me?

If @mastra/agent-browser 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/agent-browser part of a known attack campaign?

Yes — @mastra/agent-browser is associated with the GHSA-ph9v-3f5h-hg6p, IN-MAL-2026-009415 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/agent-browser 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/agent-browser (version 0.3.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @mastra/agent-browser across your stack and pipelines.

Malicious package

@mastra/agent-browsernpm

@mastra/agent-browser is a confirmed malicious npm package (MAL-2026-5996) that steals credentials and exfiltrates sensitive data (malicious version 0.3.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in @mastra/agent-browser (npm)

MAL-2026-5996

Immediate action

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

npm uninstall @mastra/agent-browser

What this malware does

@mastra/[email protected] declares a dependency on 'easy-day-js@^1.11.21' in package.json, but the package's own compiled code in dist/index.js never imports or references easy-day-js (only @mastra/core, agent-browser, and zod are used). The dependency name resembles the popular 'dayjs' library and pulling it in at install time means every installer of @mastra/agent-browser also fetches and executes whatever easy-day-js contains. The wrapper package's own code shows no install hooks, no obfuscation, and no exfiltration behavior, so the installer-side risk depends entirely on the contents of easy-day-js. Routing to human review so the transitive can be evaluated and, if malicious, both packages handled together.

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

0.3.2

Indicators of compromise (SHA-256)

f47e1be40751417e2e8e62b23068d7f74df247fc0c2b47cdf0b7ddb9733ca2f4

49ba6a41e7e43733a8334968ce740af8771208c66c7529d9f4319bd62e39601d

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/agent-browser (version 0.3.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @mastra/agent-browser across your stack and pipelines.
If you installed it — respond
@mastra/agent-browser 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/agent-browser 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/agent-browser 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/agent-browser on npm has been identified as a malicious package (version 0.3.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

GHSA-ph9v-3f5h-hg6pIN-MAL-2026-009415

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks @mastra/agent-browser-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

All malware advisories How O3 detects malware Vulnerability database