Integer underflow in the SSLv2 support in Mozilla Network Security Services (NSS) before 3.11.5, as used by Firefox before 1.5.0.10 and 2.x before 2.0.0.2, SeaMonkey before 1.0.8, Thunderbird before 1.5.0.10, and certain Sun Java System server products before 20070611, allows remote attackers to execute arbitrary code via a crafted SSLv2 server message containing a public key that is too short to encrypt the "Master Secret", which results in a heap-based overflow.