Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox before 37.0 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.

Mozilla Firefox before 37.0 does not require an HTTPS session for lightweight theme add-on installations, which allows man-in-the-middle attackers to bypass an intended user-confirmation requirement by deploying a crafted web site and conducting a DNS spoofing attack against a mozilla.org subdomain.