Mozilla Firefox 1.x before 1.5 and 1.0.x before 1.0.8, Mozilla Suite before 1.7.13, and SeaMonkey before 1.0 allows remote attackers to inject arbitrary Javascript into other sites by (1) "using a modal alert to suspend an event handler while a new page is being loaded", (2) using eval(), and using certain variants involving (3) "new Script;" and (4) using window.proto to extend eval, aka "cross-site JavaScript injection".
Exploitability
AV:NAC:MAu:NImpact
C:NI:PA:N4.3/AV:N/AC:M/Au:N/C:N/I:P/A:N