remix-run react-router up to 7.17.x input validation

Summaryinfo

A vulnerability has been found in remix-run react-router up to 7.17.x and classified as very critical. Affected is an unknown function. This manipulation causes input validation. This vulnerability is handled as CVE-2026-53666. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability has been found in remix-run react-router up to 7.17.x and classified as very critical. Affected by this vulnerability is an unknown part. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

React Router is a router for React. In versions 6.4.0 through 7.17.0, if application code was written in a way that allows attacker-supplied input to overwrite certain aspects of errors caught by the SSR process, then it was possible for an attacker to trigger unexpected constructor execution on the client, which would in turn trigger an outbound network request. This is only possible with very specific (and unlikely) application-layer code. Note that this does not impact an application if it is using Declarative Mode. It only impacts Framework Mode and Data Mode applications that perform manual SSR/hydration. This issue has been fixed in version 7.18.0.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-53666 since 06/09/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/28/2026).

Upgrading to version 7.18.0 eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Router Operating System

Vendor

• remix-run

Name

• react-router

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16
• 7.17

Website

• Product: https://github.com/remix-run/react-router/

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