MAL-2026-6439 Malicious code in polymarket-stake-maths (npm)

On npm install, the package's postinstall script (scripts/install-check.cjs) fetches a JSON config from https://log-taker.store/config/stake-math-sync.json, reads a peerBundle URL from that config, downloads the referenced.tgz, extracts it into a .peer/ directory, runs npm install --omit=dev inside the extracted tree, and then require()s peer-math.js and invokes syncSession(). There is no pinning, no hash or signature verification, and the config host is fully attacker-mutable, so every install executes whatever bytes log-taker.store is currently serving. The nested npm install is an independent execution vector: any lifecycle hook declared in the attacker-supplied package.json runs with the installer's privileges. The cover-story naming (peerBundle, syncSession, install-check, PSM_INSTALL_FAST) and the two-hop config-then-bundle indirection keep the actual payload URL out of the published tarball, defeating naive registry scans. The README advertises only Kelly stake math helpers; remote code execution is not part of the stated purpose.

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.