Malicious sites can display a spoofed location bar on a subsequently loaded page when the existing location bar on the new page is scrolled out of view if navigations between pages can be timed correctly. Note: This issue only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 51.

A location bar spoofing attack where the location bar of loaded page will be shown over the content of another tab due to a series of JavaScript events combined with fullscreen mode. Note: This issue only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 51.

The "mozAddonManager" allows for the installation of extensions from the CDN for addons.mozilla.org, a publicly accessible site. This could allow malicious extensions to install additional extensions from the CDN in combination with an XSS attack on Mozilla AMO sites. This vulnerability affects Firefox < 51.

Weak proxy objects have weak references on multiple threads when they should only have them on one, resulting in incorrect memory usage and corruption, which leads to potentially exploitable crashes. Note: This issue only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 51.

Special "about:" pages used by web content, such as RSS feeds, can load privileged "about:" pages in an iframe. If a content-injection bug were found in one of those pages this could allow for potential privilege escalation. This vulnerability affects Firefox < 51.

The JSON viewer in the Developer Tools uses insecure methods to create a communication channel for copying and viewing JSON or HTTP headers data, allowing for potential privilege escalation. This vulnerability affects Thunderbird < 45.7, Firefox ESR < 45.7, and Firefox < 51.

WebExtensions could use the "mozAddonManager" API by modifying the CSP headers on sites with the appropriate permissions and then using host requests to redirect script loads to a malicious site. This allows a malicious extension to then install additional extensions without explicit user permission. This vulnerability affects Firefox < 51.

A STUN server in conjunction with a large number of "webkitRTCPeerConnection" objects can be used to send large STUN packets in a short period of time due to a lack of rate limiting being applied on e10s systems, allowing for a denial of service attack. This vulnerability affects Firefox < 51.

The existence of a specifically requested local file can be found due to the double firing of the "onerror" when the "source" attribute on a "<track>" tag refers to a file that does not exist if the source page is loaded locally. This vulnerability affects Firefox < 51.

WebExtension scripts can use the "data:" protocol to affect pages loaded by other web extensions using this protocol, leading to potential data disclosure or privilege escalation in affected extensions. This vulnerability affects Firefox ESR < 45.7 and Firefox < 51.