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.

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 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.

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 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.

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.

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.

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.

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.

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.