CVE-2026-55685: Shopify React-Router

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

React Router is a router for React. In versions 7.0.0 through 7.17.0, the manifest endpoint could be accessed via unauthenticated targeted requests that would put heavy load on the server and slow down response times. This issue is a follow up to CVE-2026-42342, and does not does not impact React Router applications using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>). This issue has been fixed in version 7.18.0.

Affected products

• Shopify React-Router: from 7.0.0, before 7.18.0 (fixed in 7.18.0)

Published 2026-07-27. Last modified 2026-08-03.