CVE-2026-53667 React Router: RSCErrorHandler Missing Protocol Validation (XSS)
Attackers can execute scripts via untrusted redirects in React Router when using unstable RSC APIs, requiring an upgrade to the latest version.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-53667?
CVE-2026-53667 is a medium-severity cross-site scripting vulnerability in remix-run react-router, published on 27 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
React Router is a router for React. In versions 7.11.0 through 7.17.0, the RSCErrorHandler is missing protocol validation, allowing for redirects from untrusted sources. This issue is a follow up to CVE-2026-53667, and only affects consuming applications if they are using the unstable RSC APIs. This issue has been fixed in version 7.18.0.
Weakness: CWE-79
Which versions are affected by CVE-2026-53667?
2 open source packages ship an affected version, including react-router. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
react-router npm | From 7.11.0 | 7.18.0 |
react-router npm | From 7.11.0 | 7.18.0 |
Products include Shopify React-Router.
How do I fix CVE-2026-53667?
Upgrade react-router to 7.18.0 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-53667 being exploited?
There is no known exploitation of CVE-2026-53667 in the wild and no public exploit code.
Other vulnerabilities in remix-run react-router
- CVE-2026-55685 React Router: Unauthenticated Denial of Service via Inefficient Route Matching
- CVE-2026-21884 React Router SSR XSS in ScrollRestoration
- CVE-2026-42211 React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE
- CVE-2026-33245 React Router vulnerable to XSS in unstable RSC redirect handling via javascript: redirect targets
- CVE-2026-22029 React Router vulnerable to XSS via Open Redirects
Sources
Also known as GHSA-h8fp-f39c-q6mh, ROOT-APP-NPM-CVE-2026-53667.