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CVE-2026-53666— React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration

Quick assessment

Affected
remix-run react-router
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

remix-run react-router是remix-run的路由管理库。 remix-run react-router 6.4.0版本至7.17.0版本存在代码注入漏洞，该漏洞源于应用程序代码允许攻击者输入覆盖SSR过程中的错误处理，可能导致未预期的构造函数执行和外部网络请求。

CVSS 6.1 · Medium EPSS 0.42% · P34

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
remix-run react-router >= 6.4.0, < 7.18.0 affected
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I. Basic Information for CVE-2026-53666

Vulnerability Information
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Vulnerability Title
React Router: Arbitrary Constructor Injection via deserializeErrors() in React Router SSR Hydration
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
使用外部可控制的输入来选择类或代码(不安全的反射)
Source: CVE Program / CVE List V5
Vulnerability Title
remix-run react-router 代码注入漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
remix-run react-router是remix-run的路由管理库。 remix-run react-router 6.4.0版本至7.17.0版本存在代码注入漏洞，该漏洞源于应用程序代码允许攻击者输入覆盖SSR过程中的错误处理，可能导致未预期的构造函数执行和外部网络请求。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
remix-run react-router >= 6.4.0, < 7.18.0 -

II. Public POCs for CVE-2026-53666

# POC Description Source Link Shenlong Link
AI-Generated POC Verified env Premium
Reproduced successfully in a real sandbox · Below is the actual recording of building the environment and exploiting the vulnerability.
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claude_code · 4749 chars
GitHub 复现环境（可 clone 直接跑）
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III. Intelligence Information for CVE-2026-53666

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Patches & Fixes for CVE-2026-53666 (2)

Vendor Advisories for CVE-2026-53666 (1)

Vendor Pages for CVE-2026-53666 (1)

Same Patch Batch · remix-run · 2026-07-27 · 5 CVEs total

CVE-2026-55685 8.7 HIGH React Router: Unauthenticated Denial of Service via Inefficient Route Matching
CVE-2026-53667 6.9 MEDIUM React Router: Cross-site Scripting is Possible due to Missing RSCErrorHandler Protocol Val
CVE-2026-53668 6.9 MEDIUM React Router: Open redirect can lead to XSS
CVE-2026-53669 5.1 MEDIUM React Router: Open redirect via backslash in <Link> and useNavigate (CVE-2025-68470 bypass

IV. Related Vulnerabilities

Same product: react-router
Same vendor: remix-run
Same weakness: CWE-470

V. Comments for CVE-2026-53666

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