Description
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.
Published: 2026-07-27
Score: 6.1 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-337j-9hxr-rhxg React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
History

Tue, 28 Jul 2026 01:00:00 +0000

Type Values Removed Values Added
First Time appeared Remix-run
Remix-run react-router
Vendors & Products Remix-run
Remix-run react-router

Mon, 27 Jul 2026 23:30:00 +0000

Type Values Removed Values Added
Description 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.
Title React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
Weaknesses CWE-470
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}


Subscriptions

Remix-run React-router
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-27T21:14:49.547Z

Reserved: 2026-06-09T20:50:36.877Z

Link: CVE-2026-53666

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-28T00:45:02Z

Weaknesses