CVE-2026-53663
LOWCVE-2026-53663 is a low-severity (CVSS 3.1) Cross-Site Request Forgery (CSRF) vulnerability in react-router. O3 Security confirms whether CVE-2026-53663 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
React Router: `handleDocumentRequest` CSRF check covers `POST` only; PUT/PATCH/DELETE bypass
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
react-routernpm@remix-run/server-runtimenpmDescription
React Router is a router for React. From 7.12.0 until 7.15.1, certain CSRF checks in React Router v7 Framework Mode were insufficient and run on POST requests, but were bypassed on PUT/PATCH/DELETE requests. This is a low severity vulnerability because modern browser protections (CORS preflight, SameSite cookies) already block the cross-origin attack vectors that this missing CSRF check would otherwise gate. This vulnerability is fixed in 7.15.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | react-router | ≥ 7.12.0&&< 7.15.1 | 7.15.1 |
| 📦npm | @remix-run/server-runtime | ≥ 2.17.3&&< 2.17.5 | 2.17.5 |
Detection & mitigation playbook
Open-source dependencyDetect
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.
Fix
Update react-router to 7.15.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-53663 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 pinpoints whether CVE-2026-53663 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 CVE-2026-53663. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-53663 in your dependencies?
O3 detects CVE-2026-53663 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.