CVE 2006-1730
Integer overflow in Mozilla Firefox and Thunderbird 1.x before 1.5.0.2 and 1.0.x before 1.0.8, Mozilla Suite before 1.7.13, and SeaMonkey before 1.0.1 allows remote attackers to execute arbitrary code via a large number in the CSS letter-spacing property that leads to a heap-based buffer overflow.
See the 
CVE page on Mitre.org
for more details.
