React Router: Potential CSRF via PUT/PATCH/DELETE document requests

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

3.1 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS

• CVE-2026-53663: 0.15% estimated exploitation activity in the next 30 days; percentile 4.00 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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. [!NOTE] This does not impact your React Router application if you are using Declarative Mode (<BrowserRouter) or Data Mode (createBrowserRouter/<RouterProvider).

Published by the source

15 Jun 2026, 20:06 UTC

Last modified by the source

10 Sep 2026, 03:51 UTC

Source last checked

26 Oct 2026, 12:55 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-84g9-w2xq-vcv6

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-84g9-w2xq-vcv6

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# Patch Next advisory brief: CVE-2026-53663

Advisory: React Router: Potential CSRF via PUT/PATCH/DELETE document requests
IDs: CVE-2026-53663, GHSA-84g9-w2xq-vcv6
Record: https://patchnext.com/advisories/cve-2026-53663 (revision 2, source checked 26 Oct 2026, 12:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: react-router 7.15.1; @remix-run/server-runtime 2.17.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm react-router: affected >= 7.12.0, < 7.15.1; fixed in 7.15.1
- npm @remix-run/server-runtime: affected >= 2.17.3, < 2.17.5; fixed in 2.17.5

## Suggested inspection (read-only)
- `npm ls react-router --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @remix-run/server-runtime --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on react-router, @remix-run/server-runtime.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-84g9-w2xq-vcv6 (OSV record GHSA-84g9-w2xq-vcv6 lists affected ranges: npm react-router >=7.12.0 =2.17.3 <2.17.5 (fixed))
- Verified: https://github.com/advisories/GHSA-84g9-w2xq-vcv6 (GitHub-reviewed advisory GHSA-84g9-w2xq-vcv6 lists affected ranges: npm react-router >=7.12.0 =2.17.3 <2.17.5)

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