Memory safety bugs were reported in Firefox 56. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 57.
A use-after-free vulnerability can occur when flushing and resizing layout because the "PressShell" object has been freed while still in use. This results in a potentially exploitable crash during these operations. This vulnerability affects Firefox < 57, Firefox ESR < 52.5, and Thunderbird < 52.5.
The Resource Timing API incorrectly revealed navigations in cross-origin iframes. This is a same-origin policy violation and could allow for data theft of URLs loaded by users. This vulnerability affects Firefox < 57, Firefox ESR < 52.5, and Thunderbird < 52.5.
A vulnerability where the security wrapper does not deny access to some exposed properties using the deprecated "_exposedProps_" mechanism on proxy objects. These properties should be explicitly unavailable to proxy objects. This vulnerability affects Firefox < 57.
The combined, single character, version of the letter 'i' with any of the potential accents in unicode, such as acute or grave, can be spoofed in the addressbar by the dotless version of 'i' followed by the same accent as a second character with most font sets. This allows for domain spoofing attacks because these combined domain names do not display as punycode. This vulnerability affects Firefox < 57.
Some Arabic and Indic vowel marker characters can be combined with Latin characters in a domain name to eclipse the non-Latin character with some font sets on the addressbar. The non-Latin character will not be visible to most viewers. This allows for domain spoofing attacks because these combined domain names do not display as punycode. This vulnerability affects Firefox < 57.
A "data:" URL loaded in a new tab did not inherit the Content Security Policy (CSP) of the original page, allowing for bypasses of the policy including the execution of JavaScript. In prior versions when "data:" documents also inherited the context of the original page this would allow for potential cross-site scripting (XSS) attacks. This vulnerability affects Firefox < 57.
Mixed content blocking of insecure (HTTP) sub-resources in a secure (HTTPS) document was not correctly applied for resources that redirect from HTTPS to HTTP, allowing content that should be blocked, such as scripts, to be loaded on a page. This vulnerability affects Firefox < 57.
The "pingsender" executable used by the Firefox Health Report dynamically loads a system copy of libcurl, which an attacker could replace. This allows for privilege escalation as the replaced libcurl code will run with Firefox's privileges. Note: This attack requires an attacker have local system access and only affects OS X and Linux. Windows systems are not affected. This vulnerability affects Firefox < 57.