CVE-2026-100768 in Firefox
Summary
by MITRE • 09/29/2026
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 vulnerability represents a critical memory management error within the Mozilla Firefox browser, specifically located in the Graphics subsystem responsible for handling WebGPU operations. A use-after-free condition occurs when software continues to utilize a pointer after the memory it references has been reallocated or freed by the system. In this specific context, the flaw resides in how the WebGPU implementation manages object lifecycles during rendering and state transitions. When an application interacts with the GPU via the WebGPU API, the browser must allocate resources for textures, buffers, and shader programs while simultaneously tracking their usage to ensure they are not destroyed prematurely. The vulnerability arises when a reference to a graphics resource is retained by one part of the codebase after that resource has been deallocated or invalidated by another component, typically due to race conditions in asynchronous GPU command processing or improper cleanup sequences during context destruction.
From a technical perspective, this flaw allows for arbitrary read and write access to memory regions that are no longer owned by the application. Because WebGPU operates at a low level close to the hardware driver interface, an attacker can potentially craft malicious web content that triggers specific rendering commands designed to exploit the timing window between resource deallocation and subsequent pointer dereference. This scenario is particularly dangerous because it bypasses many of the standard sandboxing protections inherent in browser architectures. The vulnerability aligns with CWE-416, which classifies use-after-free errors as a distinct category of memory corruption vulnerabilities that lead to undefined behavior within the executing process. Such conditions are notoriously difficult to detect through static analysis alone and often require sophisticated fuzzing techniques targeting the graphics pipeline to reproduce reliably.
The operational impact of this vulnerability is severe, potentially leading to remote code execution on the victim's machine if exploited successfully. An attacker could leverage the arbitrary memory write capability to overwrite function pointers or return addresses within the browser process heap, thereby gaining control over program flow. This can result in the installation of malware, theft of sensitive data such as session cookies and credentials stored by the browser, or complete compromise of the underlying operating system privileges depending on the execution context of the Firefox process. Furthermore, even if remote code execution is not achieved immediately, use-after-free vulnerabilities often facilitate information disclosure attacks where an attacker can read adjacent memory contents to leak cryptographic keys or other sensitive internal states of the application.
In terms of threat modeling and industry frameworks, this vulnerability maps directly to MITRE ATT&CK technique T1203, which covers Exploitation for Client Execution, as well as techniques related to Memory Corruption such as T1499 if it leads to persistent system compromise. The attack vector is classified as Network-based with a low complexity requirement from the perspective of the attacker, who only needs to host or redirect a victim to a malicious webpage containing the exploit code. This highlights the critical importance of robust memory safety in browser components that process untrusted input from the web ecosystem.
Mitigation for this vulnerability was implemented by Mozilla and released in Firefox version 157. Users are strongly advised to update their browsers immediately to ensure they possess the patched logic that correctly manages resource lifecycles within the WebGPU implementation. Beyond updating, organizations should enforce strict content security policies to limit the execution of untrusted scripts and consider deploying browser isolation technologies or sandboxing solutions to reduce the blast radius in case a zero-day vulnerability is encountered before an update can be applied. Regular patch management cycles are essential for maintaining defense-in-depth against memory corruption vulnerabilities that target high-privilege components like graphics drivers and rendering engines.