The React Developer Tools extension registers a message listener with window.addEventListener('message', <listener>) in a content script that is accessible to any webpage that is active in the browser. Within the listener is code that requests a URL derived from the received message via fetch(). The URL is not validated or sanitised before it is fetched, thus allowing a malicious web page to arbitrarily fetch URL’s via the victim's browser.
Conclusion & alert: CVE-2023-5654 is rated Low Risk (35.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.09%).Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
Exploit prediction scoring system (EPSS) score for CVE-2023-5654
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).