CVE-2026-117988 in Firefox
Summary
by MITRE • 10/27/2026
Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.
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Analysis
by VulDB Data Team • 10/27/2026
The identified security flaw resides within the CanvasWebGL subsystem of Mozilla Firefox, specifically involving an error in how boundary conditions are evaluated during graphics rendering operations. WebGL is a JavaScript API for rendering interactive two-dimensional and three-dimensional graphics within any compatible web browser without the use of plug-ins. The vulnerability stems from incorrect handling of memory boundaries or array indices when processing specific graphical commands sent to the GPU via the CanvasWebGL interface. This type of defect typically allows an attacker who controls the input data, such as a maliciously crafted WebGL scene or shader program, to trigger out-of-bounds reads or writes in the browser's process space.
From a technical perspective, this issue represents a classic memory safety vulnerability where the software fails to properly validate that requested operations remain within allocated limits. In the context of web browsers, which operate with significant privileges on the user's system, such boundary condition errors can lead to arbitrary code execution if exploited effectively. The Graphics: CanvasWebGL component is responsible for translating high-level JavaScript commands into low-level OpenGL or Direct3D calls. If the internal checks that ensure data integrity and memory safety are bypassed due to flawed logic in boundary verification, an attacker could potentially write to unintended memory locations. This can result in corruption of critical browser structures, leading to a crash or, more severely, the execution of arbitrary code with the privileges of the user running the browser.
The operational impact of this vulnerability is severe because it facilitates sandbox escape scenarios. Modern browsers rely on process isolation and sandboxes to contain potential exploits within limited privilege contexts. By exploiting incorrect boundary conditions in the graphics subsystem, an attacker can potentially break out of these restrictive environments. This means that a victim visiting a malicious website containing exploit code could have their system compromised entirely. The attacker would gain the ability to execute arbitrary commands, access sensitive data stored locally such as cookies and passwords, install malware, or use the machine for further attacks in a networked environment. Given that WebGL is widely used for gaming, visualization tools, and complex web applications, the attack surface is substantial, affecting users across various industries who rely on rich graphical content online.
This vulnerability aligns with CWE-125, Out-of-bounds Read, or CWE-787, Out-of-bounds Write, depending on whether the exploit primarily reads sensitive memory data or overwrites it to achieve control flow hijacking. In terms of offensive security frameworks, this falls under MITRE ATT&CK technique T1059, Command and Scripting Interpreter, as part of a broader chain leading to initial access and privilege escalation through browser exploitation techniques like T1203, Exploitation for Client Execution. The flaw highlights the critical importance of rigorous input validation in graphics processing pipelines where performance optimizations sometimes lead developers to skip comprehensive boundary checks.
Mitigation strategies primarily involve applying the vendor-provided patches that address these logical errors within the CanvasWebGL component. Users must ensure they are running Firefox version 159 or later, including the Extended Support Release (ESR) version 153.6 and subsequent updates. For organizations managing large fleets of browsers, automated patch management systems should be configured to prioritize security updates for browser components that handle untrusted graphical input. Additionally, defense-in-depth measures such as enabling hardware acceleration sandboxing features where available can help limit the impact if a similar vulnerability is discovered in the future. Security teams should also monitor for indicators of compromise related to WebGL-based exploits and ensure that endpoint detection and response solutions are updated to recognize patterns associated with browser memory corruption attacks.