CVE-2023-5654: Facebook React-Devtools

Medium severity, CVSS 6.5. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Facebook React-Devtools: before 4.28.4 (fixed in 4.28.4)

Published 2023-10-19. Last modified 2026-06-17.