Answer in brief
CVE-2026-53667 records a Medium severity (CVSS 6.9) vulnerability in React Router: RSCErrorHandler Missing Protocol Validation (XSS). The current sources do not mark it as known exploited. The current feed maps react-router (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps react-router (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| react-routernpm | >=7.11.0 <7.18.0 | 7.18.0 |
Published upstream
Jul 23, 2026
Evidence: source:osv:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:recordFirst seen by HOL
Aug 3, 2026
This is a follow up to https://github.com/remix-run/react-router/security/advisories/GHSA-8646-j5j9-6r62. React Router was alerted of a code path in the (unstable) RSC error handling path in which redirects from untrusted sources could still result in an XSS vector via attacker-supplied redirect targets > [!NOTE] > This only affects your application if you are using the unstable RSC APIs
Quoted source text, attributed separately from HOL analysis.