CVE-2012-0459: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 3.9% chance of exploitation in the next 30 days.

The Cascading Style Sheets (CSS) implementation in Mozilla Firefox 4.x through 10.0, Firefox ESR 10.x before 10.0.3, Thunderbird 5.0 through 10.0, Thunderbird ESR 10.x before 10.0.3, and SeaMonkey before 2.8 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via dynamic modification of a keyframe followed by access to the cssText of the keyframe.

Affected products

• Mozilla Firefox: version 4.0 only; version 4.0.1 only; version 5.0 only; version 5.0.1 only; version 6.0 only; version 6.0.1 only; …
• Mozilla Firefox ESR: version 10.1 only; version 10.2 only
• Mozilla Seamonkey: up to and including 2.7; version 1.0 only; version 1.0.1 only; version 1.0.2 only; version 1.0.3 only; version 1.0.4 only; …
• Mozilla Thunderbird: version 5.0 only; version 6.0 only; version 6.0.1 only; version 6.0.2 only; version 7.0 only; version 7.0.1 only; …
• Mozilla Thunderbird ESR: version 10.0 only; version 10.0.1 only; version 10.0.2 only

Published 2012-03-14. Last modified 2026-06-16.