CVE-2015-4498: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 2.7% chance of exploitation in the next 30 days.

The add-on installation feature in Mozilla Firefox before 40.0.3 and Firefox ESR 38.x before 38.2.1 allows remote attackers to bypass an intended user-confirmation requirement by constructing a crafted data: URL and triggering navigation to an arbitrary http: or https: URL at a certain early point in the installation process.

Affected products

• Mozilla Firefox: up to and including 40.0.2; version 38.0 only; version 38.0.1 only; version 38.0.5 only; version 38.1.0 only; version 38.2.0 only

Published 2015-08-29. Last modified 2026-06-17.