Sign in
Deutsch English Español Polski
Medium

React Router: RSCErrorHandler Missing Protocol Validation (XSS)

  • Disclosed: 23.07.2026
  • Updated: 11.10.2026 10:22

This is a follow up to https://github.com/remix-run/react-router/security/advisories/GHSA-8646-j5j9-6r62. React Router was alerted of a code path in the (unstable) RSC error handling path in which redirects from untrusted sources could still result in an XSS vector via attacker-supplied redirect targets

[!NOTE] This only affects your application if you are using the unstable RSC APIs

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package react-router >= 7.11.0, < 7.18.0 7.18.0

References

CVSS score 6.9/10
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N
Weakness (CWE)
CWE-79
Platform
npm
Package
react-router
Disclosed
23.07.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-h8fp-f39c-q6mh - CC BY 4.0

Vulnerability history: react-router

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (20) in the archive
Total entries
20
First → latest
04.2025 07.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 11
  • Medium 8
  • Low 1

Disclosures per year

Severity:
  1. React Router: RSC Mode CSRF Bypass Allows Action Execution Before 400 Response
    High ghsa-qwww-vcr4-c8h2 >= 7.12.0, < 7.18.2, >= 8.0.0, < 8.3.0 7.18.2, 8.3.0
  2. React Router: Unauthenticated Denial of Service via Inefficient Route Matching
    High CVE-2026-55685 >= 7.0.0, < 7.18.0 7.18.0
  3. React Router: RSCErrorHandler Missing Protocol Validation (XSS) this entry
    Medium · 6.9 CVE-2026-53667 >= 7.11.0, < 7.18.0 7.18.0
  4. React Router vulnerable to Denial of Service via reflected user input in single-fetch
    High · 7.5 CVE-2026-34077 >= 7.0.0, < 7.14.0 7.14.0
  5. React Router vulnerable to DoS via unbounded path expansion in __manifest endpoint
    High · 7.5 CVE-2026-42342 >= 7.0.0, < 7.15.0 7.15.0
  6. React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE
    High · 8.1 CVE-2026-42211 >= 7.0.0, < 7.14.2 7.14.2
  7. React Router vulnerable to XSS in unstable RSC redirect handling via javascript: redirect targets
    High · 8.0 CVE-2026-33245 >= 7.7.0, < 7.13.2 7.13.2
  8. React Router vulnerable to XSS via Open Redirects
    High · 8.0 CVE-2026-22029 >= 7.0.0, < 7.12.0 7.12.0
  9. React Router SSR XSS in ScrollRestoration
    High · 8.2 CVE-2026-21884 >= 7.0.0, < 7.12.0 7.12.0
  10. React Router has XSS Vulnerability
    High · 7.6 CVE-2025-59057 >= 7.0.0, < 7.9.0 7.9.0
  11. React Router allows pre-render data spoofing on React-Router framework mode
    High · 8.2 CVE-2025-43865 >= 7.0.0-pre.0, < 7.5.2 7.5.2
  12. React Router allows a DoS via cache poisoning by forcing SPA mode
    High · 7.5 CVE-2025-43864 >= 7.2.0, < 7.5.2 7.5.2

Know which vulnerabilities affect your application

With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.

Connect your application
DockRay newsletter

Application security in your inbox

Important vulnerabilities, actionable guidance and practical advice for your applications. Choose your technologies and follow what matters to your project.

  • A daily digest of new vulnerabilities, critical ones included.
  • Notifications about important updates.
  • Practical advice on application security and monitoring.

Leave empty to receive updates for every technology.

Privacy policy

Free to subscribe. Unsubscribe with one click in any email.