What’s Vulnerable › Vulnerabilities

CVE-2026-53667: React Router: Cross-site Scripting is Possible due to Missing RSCErrorHandler Protocol Validation (Incomplete fix for CVE-2026-53667)

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-27 · updated 2026-10-24
• Weakness: CWE-79

Description

React Router is a router for React. In versions 7.11.0 through 7.17.0, the RSCErrorHandler is missing protocol validation, allowing for redirects from untrusted sources. This issue is a follow up to CVE-2026-53667, and only affects consuming applications if they are using the unstable RSC APIs. This issue has been fixed in version 7.18.0.

Affected products

• remix-run react-router: from 7.11.0 before 7.18.0 — fixed in 7.18.0

How to fix

Upgrade to a fixed version: remix-run react-router 7.18.0. Check the vendor advisory for mitigations.

References

• https://github.com/remix-run/react-router/blob/main/CHANGELOG.md#v7180
• https://github.com/remix-run/react-router/commit/ce596e823f0d7b883a433af1d5a839a8b9fe0242
• https://github.com/remix-run/react-router/pull/15177
• https://github.com/remix-run/react-router/releases/tag/react-router@7.18.0
• https://github.com/remix-run/react-router/security/advisories/GHSA-h8fp-f39c-q6mh

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