Mozilla Firefox before 1.5.0.7, Thunderbird before 1.5.0.7, and SeaMonkey before 1.0.5 allows remote attackers to cause a denial of service (crash) via a malformed JavaScript regular expression that ends with a backslash in an unterminated character set ("[\\"), which leads to a buffer over-read.
Mozilla Firefox before 1.5.0.7 and Thunderbird before 1.5.0.7 makes it easy for users to accept self-signed certificates for the auto-update mechanism, which might allow remote user-assisted attackers to use DNS spoofing to trick users into visiting a malicious site and accepting a malicious certificate for the Mozilla update site, which can then be used to install arbitrary code on the next update.