🛡️ MAL-2026-4784 — react-ui-polyfills

Malicious code in react-ui-polyfills (npm)

Source: amazon-inspector

Package advertises itself as React polyfills / UI compatibility helpers but ships no React or polyfill code. The exported getPlugin() function returns a closure that fetches JSON from https://jsonkeeper.com/b/GMIHS (an anonymous, mutable paste-style host with no integrity verification) and passes the parsed.cookie field directly to eval(), executing attacker-controlled JavaScript in the consumer's process. The mismatch between the package's advertised purpose (React polyfills) and its actual contents (SVG utilities + remote-eval backdoor) indicates the name is engineered to lure React developers. Any application that imports this package and invokes getPlugin() will execute whatever JavaScript the attacker chooses to host at the jsonkeeper URL at that moment.

Source: ghsa-malware

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.