CVE-2026-53667: XSS (CVSS 6.9)

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.

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CVSS v3.1 Score

6.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0035

Probability of exploitation

0.28%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other 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/[email protected] https://github.com/remix-run/react-router/security/advisories/GHSA-h8fp-f39c-q6mh

Frequently Asked Questions

What is CVE-2026-53667? +

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. It has a CVSS v3.1 base score of 6.9 (MEDIUM).

How severe is CVE-2026-53667? +

CVE-2026-53667 has a CVSS v3.1 score of 6.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53667? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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