A flaw in handling fullscreen transitions may have inadvertently caused the application to become stuck in fullscreen mode when a modal dialog was opened during the transition. This issue left users unable to exit fullscreen mode using standard actions like pressing "Esc" or accessing right-click menus, resulting in a disrupted browsing experience until the browser is restarted. *This bug only affects the application when running on macOS. Other operating systems are unaffected.* This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

When handling keypress events, an attacker may have been able to trick a user into bypassing the "Open Executable File?" confirmation dialog. This could have led to malicious code execution. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

The application failed to account for exceptions thrown by the `loadManifestFromFile` method during add-on signature verification. This flaw, triggered by an invalid or unsupported extension manifest, could have caused runtime errors that disrupted the signature validation process. As a result, the enforcement of signature validation for unrelated add-ons may have been bypassed. Signature validation in this context is used to ensure that third-party applications on the user's computer have not tampered with the user's extensions, limiting the impact of this issue. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

A crafted URL containing Arabic script and whitespace characters could have hidden the true origin of the page, resulting in a potential spoofing attack. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

Enhanced Tracking Protection's Strict mode may have inadvertently allowed a CSP `frame-src` bypass and DOM-based XSS through the Google SafeFrame shim in the Web Compatibility extension. This issue could have exposed users to malicious frames masquerading as legitimate content. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Firefox ESR < 115.18, Thunderbird < 133, Thunderbird < 128.5, and Thunderbird < 115.18.

The executable file warning was not presented when downloading .library-ms files. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.* This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

An attacker could cause a select dropdown to be shown over another tab; this could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.

Certain WebGL operations on Apple silicon M series devices could have lead to an out-of-bounds write and memory corruption due to a flaw in Apple's GPU driver. *This bug only affected the application on Apple M series hardware. Other platforms were unaffected.* This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Firefox ESR < 115.18, Thunderbird < 133, Thunderbird < 128.5, and Thunderbird < 115.18.

Using remote content in OpenPGP encrypted messages can lead to the disclosure of plaintext. This vulnerability affects Thunderbird < 128.4.3 and Thunderbird < 132.0.1.

Potential race conditions in IndexedDB could have caused memory corruption, leading to a potentially exploitable crash. This vulnerability affects Firefox < 132 and Thunderbird < 132.