The browser engine in Mozilla Firefox 3.0.x before 3.0.18 and 3.5.x before 3.5.8, Thunderbird before 3.0.2, and SeaMonkey before 2.0.3 allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via vectors related to the nsBlockFrame::StealFrame function in layout/generic/nsBlockFrame.cpp, and unspecified other vectors.

Mozilla Network Security Services (NSS) before 3.12.3, Firefox before 3.0.13, Thunderbird before 2.0.0.23, and SeaMonkey before 1.1.18 do not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority. NOTE: this was originally reported for Firefox before 3.5.

Mozilla 1.9 M8 and earlier, Mozilla Firefox 2 before 2.0.0.15, SeaMonkey 1.1.5 and other versions before 1.1.10, Netscape 9.0, and other Mozilla-based web browsers, when a user accepts an SSL server certificate on the basis of the CN domain name in the DN field, regard the certificate as also accepted for all domain names in subjectAltName:dNSName fields, which makes it easier for remote attackers to trick a user into accepting an invalid certificate for a spoofed web site.

Integer overflow in the bitmap (BMP) decoder for Mozilla Firefox before the Preview Release, Mozilla before 1.7.3, and Thunderbird before 0.8 allow remote attackers to execute arbitrary code via wide bitmap files that trigger heap-based buffer overflows.

Mozilla Firefox 0.9.2 allows web sites to set cookies for country-specific top-level domains, such as .ltd.uk, .plc.uk, and .sch.uk, which could allow remote attackers to perform a session fixation attack and hijack a user's HTTP session. NOTE: it was later reported that 2.x is also affected.

Internet Explorer 6.0 allows web sites to set cookies for country-specific top-level domains, such as .ltd.uk, .plc.uk, and .sch.uk, which could allow remote attackers to perform a session fixation attack and hijack a user's HTTP session.

Mozilla Firefox before the Preview Release, Mozilla before 1.7.3, and Thunderbird before 0.8 allows remote attackers to perform cross-domain scripting and possibly execute arbitrary code by convincing a user to drag and drop javascript: links to a frame or page in another domain.