Updated nss, firefox and thunderbird packages fix security vulnerabilities

A race condition was found in the way NSS verified certain certificates. A remote attacker could use this flaw to crash an application using NSS or, possibly, execute arbitrary code with the privileges of the user running that application (CVE-2014-1544). 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 it (CVE-2014-1547, CVE-2014-1555, CVE-2014-1556, CVE-2014-1557). The rootcerts and nss packages have been updated to NSS 3.16.3, and the firefox and thunderbird packages have been updated to version 24.7.0, fixing these issues.