CVE-2026-109719 in Firefox
Summary
by MITRE • 10/13/2026
Race condition, use-after-free in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5.
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Analysis
by VulDB Data Team • 10/13/2026
The identified security flaw resides within the Graphics subsystem of Mozilla Firefox, specifically affecting the CanvasWebGL component which is responsible for rendering WebGL content on web pages using HTML5 canvas elements. This vulnerability manifests as a race condition coupled with a use-after-free error, representing a critical class of memory safety issues that can lead to arbitrary code execution under specific circumstances. The root cause involves improper synchronization or timing control during the lifecycle management of graphics resources, where multiple threads or asynchronous operations may interact with shared data structures without adequate locking mechanisms. This allows an attacker to manipulate the state of these objects such that a reference is retained and accessed after the underlying memory has been deallocated by another process thread or garbage collection routine.
From a technical perspective, this type of vulnerability exploits the complex interplay between JavaScript execution contexts and native C++ graphics rendering pipelines in Firefox's architecture. When WebGL content is rendered, it often involves dynamic allocation and deallocation of GPU buffers and shader programs. If the browser fails to properly serialize access to these resources or if there is a window where an object is freed while still being referenced by another active context, accessing that memory location results in undefined behavior. In modern exploit development scenarios, this can be leveraged to achieve arbitrary read/write primitives, allowing attackers to bypass security mitigations such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR). The presence of both a race condition and use-after-free indicates a significant lapse in memory management protocols within the WebGL implementation.
The operational impact of this vulnerability is severe, particularly for users who visit maliciously crafted web pages designed to trigger the specific timing conditions required to exploit the flaw. Successful exploitation could allow an attacker to execute arbitrary code on the victim's system with the privileges of the browser process. This poses a substantial risk to user privacy and system integrity, as compromised browsers can serve as gateways for further attacks including credential theft, malware installation, or lateral movement within networked environments. The severity is amplified by the widespread use of WebGL in modern web applications, making it a high-value target for automated exploitation campaigns targeting browser vulnerabilities.
This vulnerability aligns with Common Weakness Enumeration (CWE) identifiers such as CWE-362 Race Condition and CWE-416 Use After Free, which are among the most dangerous software defects due to their potential for remote code execution. In terms of the MITRE ATT&CK framework, this flaw facilitates techniques associated with Initial Access via Browser Exploitation (T1189) and potentially Privilege Escalation if browser sandboxing is bypassed through memory corruption primitives. The vulnerability has been addressed in Firefox version 158 as well as extended support releases including Firefox ESR 115.43 and Firefox ESR 153.5, indicating that the fix involves rigorous code review and testing to ensure proper synchronization of graphics resource lifecycles.
To mitigate the risks associated with this vulnerability, organizations and individual users must prioritize immediate patching by updating their browsers to the latest stable or extended support release versions mentioned above. For enterprise environments, it is advisable to implement strict content security policies that restrict the execution of untrusted WebGL scripts where possible, although complete prevention via policy alone may not be feasible given the ubiquity of canvas-based rendering in legitimate web applications. Additionally, deploying browser isolation technologies such as sandboxing or containerization can limit the blast radius if an exploit attempt is successful by restricting the privileges granted to the renderer process. Continuous monitoring for anomalous network activity originating from browsers and keeping security software updated are also recommended defensive measures while ensuring that all dependencies within the Firefox ecosystem remain current to prevent similar memory safety issues in related components.