CVE-2010-4508: Mozilla Firefox

High severity, CVSS 10.0. EPSS: 1.3% chance of exploitation in the next 30 days.

The WebSockets implementation in Mozilla Firefox 4 through 4.0 Beta 7 does not properly perform proxy upgrade negotiation, which has unspecified impact and remote attack vectors, related to an "inherent problem" with the WebSocket specification.

Affected products

• Mozilla Firefox: version 4.0 only

Published 2010-12-09. Last modified 2026-06-16.