CVE-2012-4203: Mozilla Firefox

Medium severity, CVSS 6.8. EPSS: 3.3% chance of exploitation in the next 30 days.

The New Tab page in Mozilla Firefox before 17.0 uses a privileged context for execution of JavaScript code by bookmarklets, which allows user-assisted remote attackers to run arbitrary programs by leveraging a javascript: URL in a bookmark.

Affected products

• Mozilla Firefox: up to and including 16.0.2; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; version 0.5 only; …

Published 2012-11-21. Last modified 2026-06-16.