CVE-2026-48161

Received Received - Intake

Code Execution in react18-use Hook Shim

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: GitHub, Inc.

Description

react18-use is a React 19 use hook shim. Between 2026-05-19 01:07:01 and 2026-05-19 15:20:43, the default branch contained malicious commits 7b79148d1495a2505f9277da295a98cf176f4496 through 7b79148d1495a2505f9277da295a98cf176f4496 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 2026-05-19 01:07:01 should treat the machine as compromised, rotate every credential the machine could reach, audit account activity since 2026-05-19 01:07:01, and clean local clones.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-10

Last Modified

2026-08-10

Generated

2026-08-11

AI Q&A

2026-08-11

EPSS Evaluated

N/A

NVD

CVE-2026-48161

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-506	The product contains code that appears to be malicious in nature.

Attack-Flow Graph

Executive Summary

This vulnerability involves a malicious code injection in the react18-use package. Attackers added malicious commits to the default branch that executed remote attacker-controlled code during npm install on developer machines. The code fetched and executed a JavaScript payload from an attacker-controlled server, targeting only developer workstations and skipping CI environments.

Detection Guidance

Check for the presence of src/install.js in any local clones or forks of react18-use. Inspect postinstall scripts in package.json for suspicious entries. Review npm install logs for unexpected network requests or code execution during installation.

Impact Analysis

If you installed the affected package on a developer machine between 2026-05-19 01:07:01 and 2026-05-19 15:20:43, your machine may be compromised. Attackers could gain full control over anything accessible from the Node process with your permissions. You should rotate all credentials the machine could access, audit account activity since the compromise window, and clean local clones.

Mitigation Strategies

Delete all local clones, forks, or direct-SHA URLs of react18-use. Avoid running npm install on affected checkouts. Treat any developer machine that ran npm install on or after 2026-05-19 01:07:01 as compromised. Rotate all credentials the machine could access and audit account activity since that date.

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