CVE-2026-117975 in Firefox
Summary
by MITRE • 10/27/2026
Sandbox escape due to invalid pointer in the Graphics: WebRender 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 vulnerability represents a critical security flaw within Mozilla's WebRender graphics subsystem, specifically manifesting as an invalid pointer dereference that facilitates sandbox escape. In modern web browsers like Firefox, the rendering engine operates in a restricted environment to isolate untrusted content from sensitive system resources and user data. This isolation is primarily enforced through process separation and sandboxing mechanisms designed to contain any potential exploits within a limited context. However, when WebRender processes graphical instructions or handles complex layout calculations involving invalid pointers, it can inadvertently access memory regions outside its designated boundaries. This breach of the memory safety contract allows an attacker who controls the input data for rendering operations to execute arbitrary code with higher privileges than intended by the browser's security model.
From a technical perspective, this issue falls under the category of CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer and more specifically relates to improper pointer handling that leads to out-of-bounds access or use-after-free scenarios depending on the exact memory state at the time of exploitation. The root cause lies in insufficient validation checks before dereferencing pointers derived from web content during the rendering pipeline. When WebRender encounters malformed or maliciously crafted graphical data, it may attempt to read or write using an address that does not correspond to valid allocated memory within its sandboxed process space. If this invalid pointer is subsequently used to manipulate control flow or access sensitive structures such as cross-process communication channels, it can lead to a complete compromise of the browser's isolation guarantees.
The operational impact of this vulnerability is severe because it undermines one of the primary defenses against remote code execution attacks on the web platform. An attacker could craft a malicious webpage containing specially designed graphics elements that trigger the invalid pointer condition when rendered by WebRender. Successful exploitation would allow the attacker to break out of the browser's sandbox and execute arbitrary commands on the underlying operating system with the privileges of the user running the browser. This capability enables further attacks such as data exfiltration, installation of persistent malware, or pivoting into internal network resources if the victim is connected to a corporate environment. The threat landscape associated with this flaw aligns closely with MITRE ATT&CK techniques related to initial access and privilege escalation via web application exploits, particularly those leveraging browser vulnerabilities for code execution.
Mitigation strategies primarily involve applying the vendor-provided patches that address these memory safety issues through rigorous input validation and enhanced bounds checking within the WebRender component. Users should ensure their Firefox installations are updated to version 159 or later, including the Extended Support Release (ESR) version 153.6 which incorporates similar fixes for enterprise environments relying on stable releases. Beyond software updates, defense-in-depth measures such as enabling strict content security policies and utilizing browser extensions that restrict script execution can reduce the attack surface available to potential exploiters. Additionally, keeping operating system-level sandboxing features active ensures that even if a vulnerability is successfully exploited, the blast radius remains contained within isolated processes rather than affecting the entire host system.