PT-2026-64212 · Npm · React Router

CVE-2026-53666 · Published 2026-07-23 · Updated 2026-07-23

OSV

CVSS v3.1

6.1

Medium

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

If application code allows attacker supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for attacker to trigger unexpected constructor execution on the client which would trigger outbound network traffic. This is only possible with very specific (and unlikely) application layer code.

[!NOTE] This does not impact your application if you are using Declarative Mode. This only impacts Framework Mode and Data Mode applications doing manual SSR/hydration

Fix

Weakness Enumeration

CWE-470

Related Identifiers

CVE-2026-53666

GHSA-337J-9HXR-RHXG

Affected Products

React Router

References · 7

• https://osv.dev/vulnerability/GHSA-337j-9hxr-rhxg · Vendor Advisory
• https://github.com/remix-run/react-router/releases/tag/react-router@7.18.0 · Note
• https://github.com/remix-run/react-router/blob/main/CHANGELOG.md#v7180 · Note
• https://github.com/remix-run/react-router/security/advisories/GHSA-337j-9hxr-rhxg · Note
• https://github.com/remix-run/react-router/commit/9d22943fd46c8ae4b08236425fa3549e10e9ad1a · Note
• https://github.com/remix-run/react-router · Note
• https://github.com/remix-run/react-router/pull/15175 · Note