CVE-2026-48159
CriticalCVSS 9.3Summary
The use-reducer-async library contained malicious commits in the default branch between 2026-05-18 and 2026-05-19 that executed remotely controlled code during `npm install`. The code fetched a JavaScript payload from an external server, disabled TLS verification, and executed it with the user's privileges. The attack targeted developer machines, skipping CI and cloud environments.
Risk Assessment
Developer machines that ran `npm install` during this period may be fully compromised, potentially leading to theft of credentials and other sensitive information.
Recommendation
Treat such machines as compromised, rotate all credentials, audit account activity since 2026-05-18, and clean local clones.
Original NVD description (English source)
use-reducer-async is a React useReducer with async actions. Between 2026-05-18 16:29:52 and 2026-05-19 15:26:07, the default branch contained malicious commits da72edbde5705efcec6c62e0a3dcb73687b78dc8 through df07d5711458d8b46e11dd7afaaa21e88cafabfb that executed remote attacker-controlled code on developer machines during `npm install`. The commits were removed by force-push, but local clones, forks, and direct-SHA URLs may still contain them, and `npm install` against an affected checkout will still execute the code today. The package was not published to npm. `src/install.js` was added and wired into the `postinstall` script. It fetched a JavaScript payload from an attacker-controlled HTTPS endpoint (configurable via an environment variable), disabled TLS verification, and evaluated the response as code with `require` available. Execution was deliberately skipped on CI and cloud/serverless environments, targeting developer workstations. The second-stage payload was attacker-hosted and cannot be reconstructed. Assume full compromise of anything reachable from a Node process with the user's permissions. Those who ran `npm install` against an affected checkout on a developer machine on or after 2026-05-18 16:29:52 should treat the machine as compromised, rotate every credential the machine could reach, audit account activity since 2026-05-18 16:29:52, and clean local clones.