Vulnerability · Published Jul 27, 2026 · Assigned by GitHub_M

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

Medium 6.9

In plain English

A medium-severity cross-site scripting in react-router from remix-run. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.9Medium

Exploit odds (30 days)0.4%top 70.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	react-router	7.18.0	GHSA-h8fp-f39c-q6mh

Affected products (as reported)

Vendor	Product	Versions
remix-run	react-router	>= 7.11.0, < 7.18.0

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N

References

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