use-context-selector is a React useContextSelector hook in userland Between 2026-05-18 15:57:18 and 2026-05-19 15:24:34, the default branch contained malicious commits 9d8481a513b7b0d1c0941b220c69b25de748641b through 6f2dae054ca014068bdbbb4db96006424d674124 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 15:57:18 should treat the machine as compromised, rotate every credential the machine could reach, audit account activity** since 2026-05-18 15:57:18, and clean local clones.
https://github.com/dai-shi/use-context-selector/security/advisories/GHSA-7h6v-mwq6-jhm8
Published: 2026-08-10
Updated: 2026-08-11
Base Score: 6.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P
Severity: Medium
Base Score: 9.8
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical
Base Score: 9.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Severity: Critical
EPSS: 0.00396