CVE-2026-40181 MEDIUM

CVE-2026-40181: React Router's same-origin redirect with path starting // causes open redirect via protocol-relative URL reinterpretation

Vendor Remix-Run
Product react-router
Weakness CWE-601 · Open redirect
Published June 2, 2026
Last update June 3, 2026

CVSS base score

6.6/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U

What the vulnerability does

01Description

React Router is a router for React. In versions 7.0.0 through 7.14.0 and 6.7.0 through 6.30.3, certain URLs passed to the redirect function can trigger an open redirect to an external domain due to path values starting with // being reinterpreted as protocol-relative URLs. The level of impact depends on the validation done by the application prior to returning the redirect. This does not impact applications using Declarative Mode (<BrowserRouter>). This is patched in versions 7.14.1 and 6.30.4.

Key dates

02Disclosure timeline

June 2, 2026 CVE published
June 3, 2026 Record updated