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React Router SSR XSS in ScrollRestoration

High
brophdawg11 published GHSA-8v8x-cx79-35w7 Jan 8, 2026

Package

npm @remix-run/react (npm)

Affected versions

<=2.17.2

Patched versions

>=2.17.3
npm react-router (npm)
>=7.0.0,<=7.11.0
>=7.12.0

Description

A XSS vulnerability exists in in React Router's <ScrollRestoration> API in Framework Mode when using the getKey/storageKey props during Server-Side Rendering which could allow arbitrary JavaScript execution during SSR if untrusted content is used to generate the keys.

Note

This does not impact your application if you have disabled server-side rendering in Framework Mode, or if you are using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>).

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

CVE ID

CVE-2026-21884

Weaknesses

No CWEs

Credits