Mozilla Firefox before 1.5.0.7 and SeaMonkey before 1.0.5 allows remote attackers to bypass the security model and inject content into the sub-frame of another site via targetWindow.frames[n].document.open(), which facilitates spoofing and other attacks.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.007
EPSS Ranking 71.6%