The host is installed with Mozilla Firefox 4.x through 8.0 or Thunderbird 5.0 through 8.0 or SeaMonkey before 2.6 and is prone to multiple denial of service vulnerabilities. The flaws are present in the applications, which fail to handle YARR regular expression library that could be triggered by javascript in web content. Successful exploitation could allow remote attackers to execute arbitrary code or crash the service.