CVE-2024-4776 in Firefox
Summary
by MITRE • 05/14/2024
A file dialog shown while in full-screen mode could have resulted in the window remaining disabled. This vulnerability affects Firefox < 126.
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Analysis
by VulDB Data Team • 04/02/2025
This vulnerability represents a critical window management issue in the Firefox browser that could lead to persistent UI lockout conditions during full-screen operations. The flaw occurs specifically when a file dialog is displayed while Firefox is operating in full-screen mode, creating a scenario where the application window becomes permanently disabled and unresponsive to user interactions. This type of vulnerability falls under the broader category of user interface manipulation flaws that can severely impact user experience and potentially create security implications through denial-of-service conditions.
The technical nature of this vulnerability stems from improper handling of window state management during full-screen mode transitions. When Firefox enters full-screen mode, it typically disables normal window controls and restricts user interaction with other application elements to maintain immersive experience. However, the implementation fails to properly restore window functionality when file dialogs are presented, leading to a condition where the window remains in a disabled state even after the dialog is closed. This represents a failure in proper state machine handling and window management protocols that should ensure consistent application behavior regardless of modal dialog presence.
The operational impact of this vulnerability extends beyond simple user inconvenience to potentially creating persistent system lockout scenarios. Users experiencing this issue would find themselves unable to interact with the browser window, requiring forced termination of the application through external means such as task managers or system commands. This condition could be particularly problematic for users relying on full-screen browsing for presentations, video consumption, or productivity tasks where immediate access to browser controls is essential. The vulnerability essentially creates a denial-of-service condition specific to the browser's window management system rather than affecting core security functions.
From a cybersecurity perspective, this vulnerability aligns with CWE-691, which addresses insufficient control flow management, and could potentially be leveraged in social engineering attacks where malicious actors might exploit the persistent window disablement to create convincing phishing or malware delivery scenarios. The issue also relates to ATT&CK technique T1059.001 for command and scripting interpreter usage, as users might be forced to resort to command-line tools to terminate the browser process. The vulnerability demonstrates the importance of proper state management in GUI applications and highlights how seemingly minor UI flaws can create significant operational disruptions. Users should immediately update to Firefox version 126 or later to mitigate this vulnerability, as the fix addresses the underlying window state management logic to ensure proper restoration of window functionality after modal dialogs are dismissed.