MAL-2026-5996 Malicious code in @mastra/agent-browser (npm)

@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.