Memory safety bugs present in Firefox 126. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 127.

In violation of spec, cookie prefixes such as `__Secure` were being ignored if they were not correctly capitalized - by spec they should be checked with a case-insensitive comparison. This could have resulted in the browser not correctly honoring the behaviors specified by the prefix. This vulnerability affects Firefox < 127.

By manipulating the fullscreen feature while opening a data-list, an attacker could have overlaid a text box over the address bar. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 127.

A website was able to detect when a user took a screenshot of a page using the built-in Screenshot functionality in Firefox. This vulnerability affects Firefox < 127.

If an out-of-memory condition occurs at a specific point using allocations in the probabilistic heap checker, an assertion could have been triggered, and in rarer situations, memory corruption could have occurred. This vulnerability affects Firefox < 127.

An attacker could have caused a use-after-free in the JavaScript engine to read memory in the JavaScript string section of the heap. This vulnerability affects Firefox < 127.

In addition to detecting when a user was taking a screenshot (XXX), a website was able to overlay the 'My Shots' button that appeared, and direct the user to a replica Firefox Screenshots page that could be used for phishing. This vulnerability affects Firefox < 127.

If a specific sequence of actions is performed when opening a new tab, the triggering principal associated with the new tab may have been incorrect. The triggering principal is used to calculate many values, including the `Referer` and `Sec-*` headers, meaning there is the potential for incorrect security checks within the browser in addition to incorrect or misleading information sent to remote websites. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 127.

Memory safety bugs present in Firefox 126, Firefox ESR 115.11, and Thunderbird 115.11. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.

By manipulating the text in an `&lt;input&gt;` tag, an attacker could have caused corrupt memory leading to a potentially exploitable crash. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.

Offscreen Canvas did not properly track cross-origin tainting, which could be used to access image data from another site in violation of same-origin policy. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.

On Windows 10, when using the 'Save As' functionality, an attacker could have tricked the browser into saving the file with a disallowed extension such as `.url` by including an invalid character in the extension. *Note:* This issue only affected Windows operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.

By tricking the browser with a `X-Frame-Options` header, a sandboxed iframe could have presented a button that, if clicked by a user, would bypass restrictions to open a new window. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.

By monitoring the time certain operations take, an attacker could have guessed which external protocol handlers were functional on a user's system. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.

If a garbage collection was triggered at the right time, a use-after-free could have occurred during object transplant. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.

Memory corruption in the networking stack could have led to a potentially exploitable crash. This vulnerability affects Firefox < 125, Firefox ESR < 115.12, and Thunderbird < 115.12.

The file scheme of URLs would be hidden, resulting in potential spoofing of a website's address in the location bar This vulnerability affects Focus for iOS < 126.

Memory safety bugs present in Firefox 125. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 126.

A file dialog shown while in full-screen mode could have resulted in the window remaining disabled. This vulnerability affects Firefox < 126.

An iterator stop condition was missing when handling WASM code in the built-in profiler, potentially leading to invalid memory access and undefined behavior. *Note:* This issue only affects the application when the profiler is running. This vulnerability affects Firefox < 126.

The `ShmemCharMapHashEntry()` code was susceptible to potentially undefined behavior by bypassing the move semantics for one of its data members. This vulnerability affects Firefox < 126.

When a network error occurred during page load, the prior content could have remained in view with a blank URL bar. This could have been used to obfuscate a spoofed web site. This vulnerability affects Firefox < 126.

An HTTP digest authentication nonce value was generated using `rand()` which could lead to predictable values. This vulnerability affects Firefox < 126.

A memory allocation check was missing which would lead to a use-after-free if the allocation failed. This could have triggered a crash or potentially be leveraged to achieve code execution. This vulnerability affects Firefox < 126.

Different techniques existed to obscure the fullscreen notification in Firefox for Android. These could have led to potential user confusion and spoofing attacks. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 126.

Web application manifests were stored by using an insecure MD5 hash which allowed for a hash collision to overwrite another application's manifest. This could have been exploited to run arbitrary code in another application's context. *This issue only affects Firefox for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 126.

Multiple WebRTC threads could have claimed a newly connected audio input leading to use-after-free. This vulnerability affects Firefox < 126.

Memory safety bugs present in Firefox 125, Firefox ESR 115.10, and Thunderbird 115.10. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.

When saving a page to PDF, certain font styles could have led to a potential use-after-free crash. This vulnerability affects Firefox < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.

When importing resources using Web Workers, error messages would distinguish the difference between `application/javascript` responses and non-script responses. This could have been abused to learn information cross-origin. This vulnerability affects Firefox < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.

A bug in popup notifications' interaction with WebAuthn made it easier for an attacker to trick a user into granting permissions. This vulnerability affects Firefox < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.

If the `browser.privatebrowsing.autostart` preference is enabled, IndexedDB files were not properly deleted when the window was closed. This preference is disabled by default in Firefox. This vulnerability affects Firefox < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.

A type check was missing when handling fonts in PDF.js, which would allow arbitrary JavaScript execution in the PDF.js context. This vulnerability affects Firefox < 126, Firefox ESR < 115.11, and Thunderbird < 115.11.

Memory safety bugs present in Firefox 124. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 125.

Memory safety bug present in Firefox 124, Firefox ESR 115.9, and Thunderbird 115.9. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

There was no limit to the number of HTTP/2 CONTINUATION frames that would be processed. A server could abuse this to create an Out of Memory condition in the browser. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

The executable file warning was not presented when downloading .xrm-ms files. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.* This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

The MarkStack assignment operator, part of the JavaScript engine, could access uninitialized memory if it were used in a self-assignment. This vulnerability affects Firefox < 125.

If an AlignedBuffer were assigned to itself, the subsequent self-move could result in an incorrect reference count and later use-after-free. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

An out-of-memory condition during object initialization could result in an empty shape list. If the JIT subsequently traced the object it would crash. This vulnerability affects Firefox < 125.

On 32-bit versions there were integer-overflows that led to an out-of-bounds-read that potentially could be triggered by a malformed OpenType font. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

It was possible to mutate a JavaScript object so that the JIT could crash while tracing it. This vulnerability affects Firefox < 125.

The JIT created incorrect code for arguments in certain cases. This led to potential use-after-free crashes during garbage collection. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

A use-after-free could occur during WASM execution if garbage collection ran during the creation of an array. This vulnerability affects Firefox < 125.

In certain cases the JIT incorrectly optimized MSubstr operations, which led to out-of-bounds reads. This vulnerability affects Firefox < 125.

In some code patterns the JIT incorrectly optimized switch statements and generated code with out-of-bounds-reads. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

A use-after-free could result if a JavaScript realm was in the process of being initialized when a garbage collection started. This vulnerability affects Firefox < 125.

GetBoundName could return the wrong version of an object when JIT optimizations were applied. This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

If an insecure element was added to a page after a delay, Firefox would not replace the secure icon with a mixed content security status This vulnerability affects Firefox for iOS < 124.

Dragging Javascript URLs to the address bar could cause them to be loaded, bypassing restrictions and security protections This vulnerability affects Firefox for iOS < 124.