Updated firefox packages fix security vulnerabilities:
A flaw was found in the processing of malformed web content. A web page containing malicious content could cause Firefox to crash or, potentially, execute arbitrary code with the privileges of the user running Firefox (CVE-2015-4497).
A flaw was found in the way Firefox handled installation of add-ons. An attacker could use this flaw to bypass the add-on installation prompt, and trick the user into installing an add-on from a malicious source (CVE-2015-4498).