Security issues were identified and fixed in mozilla firefox and thunderbird: Mozilla Firefox before 3.6.23 and 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 do not prevent the starting of a download in response to the holding of the Enter key, which allows user-assisted remote attackers to bypass intended access restrictions via a crafted web site . Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox before 3.6.23 and 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 allow remote attackers to cause a denial of service or possibly execute arbitrary code via unknown vectors . Unspecified vulnerability in the plugin API in Mozilla Firefox 3.6.x before 3.6.23 allows remote attackers to cause a denial of service or possibly execute arbitrary code via unknown vectors . Mozilla Firefox before 3.6.23 and 4.x through 5, Thunderbird before 6.0, and SeaMonkey before 2.3 do not properly handle location as the name of a frame, which allows remote attackers to bypass the Same Origin Policy via a crafted web site, a different vulnerability than CVE-2010-0170 . Mozilla Firefox before 3.6.23 and 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 do not properly handle HTTP responses that contain multiple Location, Content-Length, or Content-Disposition headers, which makes it easier for remote attackers to conduct HTTP response splitting attacks via crafted header values . Mozilla Firefox 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 do not prevent manual add-on installation in response to the holding of the Enter key, which allows user-assisted remote attackers to bypass intended access restrictions via a crafted web site that triggers an unspecified internal error . Integer underflow in Mozilla Firefox 3.6.x before 3.6.23 allows remote attackers to cause a denial of service or possibly execute arbitrary code via JavaScript code containing a large RegExp expression . Packages for 2009.0 are provided as of the Extended Maintenance Program