CVE-2026-42342: Shopify React-Router

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

React Router is a router for React. In versions 7.0.0 through 7.14.x of react-router and versions 2.10.0 through 2.17.4 of @remix-run/server-runtime, certain crafted requests can consume disproportionate server resources via unbounded path expansion in the __manifest endpoint, resulting in response time degradation and/or service unavailability for end users. This affects React Router Framework Mode applications as well as Remix applications. This does not impact applications using Declarative Mode (`<BrowserRouter>`) or Data Mode (`createBrowserRouter/<RouterProvider>`). This is patched in react-router version 7.15.0 and @remix-run/server-runtime version 2.17.5.

Affected products

• Shopify React-Router: from 7.0.0, before 7.15.0 (fixed in 7.15.0)
• Shopify Remix-Run/server-Runtime: from 2.10.0, before 2.17.5 (fixed in 2.17.5)

Published 2026-06-02. Last modified 2026-07-21.