Several flaws were found in the processing of malformed web content. A web page containing malicious content could cause Firefox or Thunderbird to crash or, potentially, execute arbitrary code with the privileges of the user running Firefox or Thunderbird (CVE-2013-1718, CVE-2013-1722, CVE-2013-1725, CVE-2013-1730, CVE-2013-1732, CVE-2013-1735, CVE-2013-1736).
A flaw was found in the way Firefox and Thunderbird handled certain DOM JavaScript objects. An attacker could use this flaw to make JavaScript client or add-on code make incorrect, security sensitive decisions (CVE-2013-1737).