A use-after-free vulnerability occurs during transaction processing in the editor during design mode interactions. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

A use-after-free vulnerability occurs when redirecting focus handling which results in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

A use-after-free vulnerability in SMIL animation functions occurs when pointers to animation elements in an array are dropped from the animation controller while still in use. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

A use-after-free vulnerability occurs during certain text input selection resulting in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

Memory safety bugs were reported in Firefox 52, Firefox ESR 52, and Thunderbird 52. 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 Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

Memory safety bugs were reported in Firefox 52, Firefox ESR 45.8, Firefox ESR 52, and Thunderbird 52. 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 Thunderbird < 52.1, Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.

An integer overflow in "createImageBitmap()" was reported through the Pwn2Own contest. The fix for this vulnerability disables the experimental extensions to the "createImageBitmap" API. This function runs in the content sandbox, requiring a second vulnerability to compromise a user's computer. This vulnerability affects Firefox ESR < 52.0.1 and Firefox < 52.0.1.

A non-existent chrome.manifest file will attempt to be loaded during startup from the primary installation directory. If a malicious user with local access puts chrome.manifest and other referenced files in this directory, they will be loaded and activated during startup. This could result in malicious software being added without consent or modification of referenced installed files. This vulnerability affects Firefox < 52.

On Linux, if the secure computing mode BPF (seccomp-bpf) filter is running when the Gecko Media Plugin sandbox is started, the sandbox fails to be applied and items that would run within the sandbox are run protected only by the running filter which is typically weak compared to the sandbox. Note: this issue only affects Linux. Other operating systems are not affected. This vulnerability affects Firefox < 52 and Thunderbird < 52.

The Gecko Media Plugin sandbox allows access to local files that match specific regular expressions. On OS OX, this matching allows access to some data in subdirectories of "/private/var" that could expose personal or temporary data. This has been updated to not allow access to "/private/var" and its subdirectories. Note: this issue only affects OS X. Other operating systems are not affected. This vulnerability affects Firefox < 52 and Thunderbird < 52.

If a malicious site uses the "view-source:" protocol in a series within a single hyperlink, it can trigger a non-exploitable browser crash when the hyperlink is selected. This was fixed by no longer making "view-source:" linkable. This vulnerability affects Firefox < 52 and Thunderbird < 52.

A malicious site could spoof the contents of the print preview window if popup windows are enabled, resulting in user confusion of what site is currently loaded. This vulnerability affects Firefox < 52 and Thunderbird < 52.

A "javascript:" url loaded by a malicious page can obfuscate its location by blanking the URL displayed in the addressbar, allowing for an attacker to spoof an existing page without the malicious page's address being displayed correctly. This vulnerability affects Firefox < 52.

If a malicious site repeatedly triggers a modal authentication prompt, eventually the browser UI will become non-responsive, requiring shutdown through the operating system. This is a denial of service (DOS) attack. This vulnerability affects Firefox < 52 and Thunderbird < 52.

An out of bounds read error occurs when parsing some HTTP digest authorization responses, resulting in information leakage through the reading of random memory containing matches to specifically set patterns. This vulnerability affects Firefox < 52 and Thunderbird < 52.

When dragging content from the primary browser pane to the addressbar on a malicious site, it is possible to change the addressbar so that the displayed location following navigation does not match the URL of the newly loaded page. This allows for spoofing attacks. This vulnerability affects Firefox < 52.

In certain circumstances a networking event listener can be prematurely released. This appears to result in a null dereference in practice. This vulnerability affects Firefox < 52 and Thunderbird < 52.

An attack can use a blob URL and script to spoof an arbitrary addressbar URL prefaced by "blob:" as the protocol, leading to user confusion and further spoofing attacks. This vulnerability affects Firefox < 52.

The file picker dialog can choose and display the wrong local default directory when instantiated. On some operating systems, this can lead to information disclosure, such as the operating system or the local account name. This vulnerability affects Firefox < 52 and Thunderbird < 52.

A segmentation fault can occur during some bidirectional layout operations. This vulnerability affects Firefox < 52 and Thunderbird < 52.