WebSocket Information Disclosure in Firefox and Firefox ESR
CVE-2026-16405

Currently unrated

Key Information:

Vendor: Mozilla
Status: Firefox
Vendor: CVE Published:; 21 July 2026

What is CVE-2026-16405?

A vulnerability affecting the Networking: WebSockets component allows unauthorized access to sensitive information within the affected versions of Firefox and Firefox ESR. Attackers could exploit this flaw to extract private data while WebSocket connections are established. This issue has been addressed in Firefox version 153 and Firefox ESR version 140.13, which users are advised to upgrade to for enhanced security.