CVE-2026-48161

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 4.0

9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M

EPSS

0.42% probability · 35th percentile

CISA KEV

Not listed

Weakness

CWE-506

Source

security-advisories@github.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.