What is CVE-2026-21884?

CVE-2026-21884 is a high-severity vulnerability in Remix-run React-router, classified under Cross-site Scripting. CVSS score: 8.2/10. Published 2026-01-10.

How severe is CVE-2026-21884?

High severity. CVSS v3 base score is 8.2 out of 10.

XSS in Remix-run React-router

CVE-2026-21884

React Router is a router for React. In @remix-run/react version prior to 2.17.3. and react-router 7.0.0 through 7.11.0, a XSS vulnerability exists in in React Router's <ScrollRestoration> API in Framework Mode when using the getKey/storage…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.000 (6.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N.

Affected products

Remix-run React-router — versions @remix-run/react < 2.17.3, react-router >= 7.0.0, < 7.12.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

https://github.com/remix-run/react-router/security/advisories/GHSA-8v8x-cx79-35w7 (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-21884?: CVE-2026-21884 is a high-severity vulnerability in Remix-run React-router, classified under Cross-site Scripting. CVSS score: 8.2/10. Published 2026-01-10.
How severe is CVE-2026-21884?: High severity. CVSS v3 base score is 8.2 out of 10.