Mozilla Responds to Critical Vulnerability: Urgent Firefox Update

Mozilla issued an urgent update to Firefox for Windows to patch a critical IPC handle-management vulnerability (CVE-2025-2857) that could allow a compromised child process to pass an overly permissive handle to a parent and escape the browser sandbox; fixed versions include Firefox 136.0.4 and ESR 115.21.1 / 128.8.1. The advisory notes similarity to an actively exploited Chrome zero-day (CVE-2025-2783) and recommends immediate patching, while CISA has added the Chrome issue to its KEV catalog and mandated federal updates.