CVE-2026-109712 in Firefox
Summary
by MITRE • 10/13/2026
Sandbox escape due to uninitialized memory in the Graphics component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/13/2026
The identified vulnerability represents a critical security flaw within the Mozilla Firefox browser's graphics subsystem, specifically involving an uninitialized memory access that facilitates sandbox escape. In modern web browsers, the rendering engine operates in a restricted environment known as a sandbox to isolate potentially malicious content from the host operating system and user data. This isolation is paramount for preventing remote code execution attacks triggered by visiting compromised or malicious websites. The flaw arises when the graphics component fails to properly initialize memory buffers before they are accessed or processed. Uninitialized memory often contains residual data from previous operations, which can include sensitive information such as pointers, stack addresses, or other control structures that were not cleared after their prior use. When an attacker crafts a specific input, typically through complex JavaScript code interacting with WebGL or Canvas APIs, they can exploit this uninitialized state to read arbitrary memory locations or manipulate the execution flow of the browser process.
The technical mechanism behind this vulnerability relies on the race conditions or logic errors inherent in how the graphics driver and the browser's rendering pipeline handle temporary buffers. By triggering a path where these buffers are used without being zeroed out, an attacker can leak internal state information that reveals memory layout details essential for bypassing security mitigations like Address Space Layout Randomization (ASLR). Furthermore, if the uninitialized data influences control flow decisions or pointer dereferences within the graphics stack, it may allow for arbitrary read and write primitives. These primitives are the foundational building blocks required to achieve sandbox escape, enabling an attacker to break out of the browser's confined environment and execute code with the privileges of the current user on the host system. This transforms a standard cross-site scripting or content injection scenario into a full remote code execution vulnerability, significantly escalating the severity from information disclosure to complete system compromise.
The operational impact of this sandbox escape is severe, as it allows an attacker who can trick a victim into loading malicious web content to gain unauthorized access to the user's file system, browser history, cookies, and saved credentials. Once inside the host environment, the malware can install persistent backdoors, exfiltrate sensitive corporate data, or pivot further within a network if the compromised machine is part of an enterprise infrastructure. The existence of such vulnerabilities in widely used software like Firefox poses a systemic risk to internet security, as they are frequently targeted by drive-by download attacks and malicious advertising networks that automatically exploit browser flaws without any user interaction beyond visiting a webpage.
This vulnerability aligns with CWE-908, which describes the use of uninitialized resource, specifically highlighting how improper initialization leads to unpredictable behavior or information leaks. From an offensive security perspective, it maps closely to MITRE ATT&CK techniques related to privilege escalation and defense evasion, particularly those involving memory corruption exploitation to bypass sandbox boundaries. The remediation for this issue was implemented in Firefox version 158, as well as the Extended Support Release versions 115.43 and 153.5. Organizations relying on these browser variants must ensure that automatic updates are enabled or manually deploy patches immediately to mitigate the risk of exploitation. Security teams should also monitor for indicators of compromise associated with sandbox escape attempts, such as unusual process spawning from browser binaries or unexpected network connections originating from Firefox processes, to detect potential active exploits in their environments before all endpoints have been patched.