CVE-2026-100761 in Firefox
Summary
by MITRE • 09/29/2026
Privilege escalation due to use-after-free in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 157.
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Analysis
by VulDB Data Team • 09/29/2026
The identified security flaw resides within the Graphics subsystem of Mozilla Firefox, specifically targeting the implementation of the WebGPU API. As a high-performance graphics and computation interface designed for modern web applications, WebGPU requires tight integration with underlying hardware acceleration drivers and browser rendering pipelines. The vulnerability is classified as an out-of-bounds write resulting from a use-after-free condition. This type of memory corruption error occurs when the application continues to access or modify memory that has already been deallocated by the system's garbage collector or explicit cleanup routines. In the context of WebGPU, this likely involves shader compilation buffers, command buffer structures, or texture data mappings where pointers are not properly invalidated after their associated resources are released.
From a technical perspective, use-after-free vulnerabilities represent one of the most dangerous classes of memory safety issues because they allow an attacker to manipulate program flow and data integrity with high precision. When the browser attempts to interact with freed memory, it may overwrite adjacent heap structures or execute arbitrary code if the freed memory is reallocated for malicious purposes by a crafted web page. The specific component involved handles complex graphical operations, meaning that successful exploitation could lead to remote code execution within the context of the user's browsing session. This bypasses many traditional sandboxing mechanisms because the graphics pipeline often operates with elevated privileges relative to standard JavaScript contexts to ensure performance and direct hardware access.
The operational impact of this vulnerability is severe, particularly for users who visit maliciously crafted websites designed to exploit WebGPU features. An attacker could leverage this flaw to escape the browser's security sandbox, gaining unauthorized access to sensitive user data such as cookies, session tokens, or locally stored files. Furthermore, because the issue affects a core rendering component, it may lead to application crashes and denial of service conditions for legitimate users relying on WebGL2 or WebGPU-based applications. The lack of proper memory management in this specific code path creates a persistent attack surface that can be triggered through standard web technologies without requiring additional plugins or external software installations.
Mitigation strategies primarily rely on the immediate deployment of Firefox version 157, which contains the necessary patches to correct the memory handling logic within the WebGPU implementation. Developers and system administrators should ensure automatic updates are enabled to prevent exposure during the window between vulnerability disclosure and patch application. For organizations deploying Firefox in enterprise environments, it is critical to verify that all client machines have received this update through their respective distribution channels. Additionally, security teams should monitor for indicators of compromise related to memory corruption events or unusual GPU driver behavior that might indicate an attempted exploitation of similar flaws in other components.
This vulnerability aligns with CWE-416, which describes the use-after-free condition where a pointer is used after it has been freed, leading to undefined behavior and potential security breaches. In terms of offensive security frameworks, this flaw facilitates techniques associated with MITRE ATT&CK Tactic TA0005 (Defense Evasion) and specifically relates to process injection or memory corruption techniques that allow attackers to bypass application sandboxing controls. The fix emphasizes the importance of rigorous static analysis and fuzz testing for graphics APIs within browsers, as these components are frequent targets due to their complexity and privileged access levels. Continuous monitoring and prompt patch management remain essential defenses against such high-severity memory safety vulnerabilities in modern web browsers.