CVE-2009-3012: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 0.8% chance of exploitation in the next 30 days.

Mozilla Firefox 3.0.13 and earlier, 3.5, 3.6 a1 pre, and 3.7 a1 pre does not properly block data: URIs in Location headers in HTTP responses, which allows remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (1) injecting a Location header that contains JavaScript sequences in a data:text/html URI or (2) entering a data:text/html URI with JavaScript sequences when specifying the content of a Location header. NOTE: the JavaScript executes outside of the context of the HTTP site.

Affected products

• Mozilla Firefox: up to and including 3.0.13; version 3.0 only; version 3.0.1 only; version 3.0.2 only; version 3.0.3 only; version 3.0.4 only; …

Published 2009-08-31. Last modified 2026-06-16.