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📦 npm

GHSA-8v8x-cx79-35w7

HIGH

React Router SSR XSS in ScrollRestoration

Also known asCVE-2026-21884
Published
Jan 8, 2026
Updated
Feb 3, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk28th percentile+0.34%
0.00%0.29%0.58%0.87%0.0%0.4%Feb 26May 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

2 pkgs affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

react-routernpm
48.7Mdownloads / week
@remix-run/reactnpm
766Kdownloads / week

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 applications if developers have disabled server-side rendering in Framework Mode, or if they are using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>).

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
📦npmreact-router7.0.0&&< 7.12.07.12.0
📦npm@remix-run/reactall versions2.17.3

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for react-router. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update react-router to 7.12.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8v8x-cx79-35w7 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-8v8x-cx79-35w7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-8v8x-cx79-35w7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

A XSS vulnerability exists in in React Router's `<ScrollRestoration>` API in [Framework Mode](https://reactrouter.com/start/modes#framework) 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 applications if developers have [disabled server-side rendering](https://reactrouter.com/how-to/spa) in Framework Mode, or if they are using [Declarative Mode](https://reactrouter.com/start/modes#declarative) (`<BrowserRouter>`) or [Data Mode
O3 Security · Impact-Aware SCA

Is GHSA-8v8x-cx79-35w7 in your dependencies?

O3 detects GHSA-8v8x-cx79-35w7 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.