CVE-2026-53666
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…
Does this matter?
Lower severity and a low EPSS score (0.30%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 0.30% probability · 23th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-470
- Affected
- shopify/react-router
- Source
- security-advisories@github.com
References
- https://github.com/remix-run/react-router/blob/main/CHANGELOG.md#v7180Release Notes
- https://github.com/remix-run/react-router/commit/9d22943fd46c8ae4b08236425fa3549e10e9ad1aPatch
- https://github.com/remix-run/react-router/pull/15175Issue Tracking, Patch
- https://github.com/remix-run/react-router/releases/tag/react-router@7.18.0Release Notes
- https://github.com/remix-run/react-router/security/advisories/GHSA-337j-9hxr-rhxgThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.