CVE-2026-92035 in Firefox
Summary
by MITRE • 09/15/2026
Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 156 and Firefox ESR 153.3.
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Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability represents a critical security flaw within the Mozilla Firefox browser's graphics rendering subsystem, specifically involving an error in how boundary conditions are evaluated during graphical operations. In modern web browsers, content is typically executed within a sandboxed environment to isolate potentially malicious code from the underlying operating system and user data. This isolation relies heavily on strict enforcement of memory boundaries and resource limits. The flaw described indicates that the graphics component failed to correctly validate or enforce these boundary conditions, allowing for an out-of-bounds read or write operation when processing specific graphical inputs. Such errors are particularly dangerous because they occur in low-level code responsible for rendering visual elements, which is often exposed to untrusted web content through standard HTML5 and WebGL APIs.
From a technical perspective, this issue aligns with the Common Weakness Enumeration category CWE-120, Buffer Copy without Checking Size of Input, or more specifically CWE-787 Out-of-bounds Write if memory corruption occurs. The incorrect boundary conditions suggest that the application did not properly check whether input data exceeded allocated limits before processing it within the graphics pipeline. This oversight enables an attacker to craft a malicious webpage containing specially designed graphical elements or scripts that trigger this logic error. By exploiting the miscalculated boundaries, an attacker can write data beyond the intended memory allocation, potentially overwriting adjacent memory structures such as function pointers, object headers, or security cookies.
The operational impact of this vulnerability is severe, classified under MITRE ATT&CK technique T1203 Exploitation for Client Execution and potentially leading to arbitrary code execution if combined with other techniques like heap spraying or ROP chain construction. Successful exploitation allows a remote attacker to bypass the browser's sandbox protections, effectively achieving escape from the restricted web content context into the broader system environment. This compromise grants the attacker full control over the victim's machine under the privileges of the current user account. The consequences include unauthorized access to sensitive files, installation of persistent malware, keystroke logging, and complete takeover of the compromised workstation. Given that graphics processing is a core function of web browsing, this vulnerability affects all users who visit maliciously crafted sites while using affected versions of Firefox.
To mitigate this risk, it is imperative for organizations and individual users to update their browsers immediately to version 156 or later, including the Extended Support Release (ESR) version 153.3 where applicable. These updates contain the necessary patches that correct the boundary condition checks within the graphics component, ensuring that input data is properly validated against allocated memory limits before processing. In environments where immediate patching may not be feasible due to compatibility concerns, network-level defenses such as web filtering proxies can be configured to block access to known malicious domains or restrict execution of complex JavaScript and WebGL content from untrusted sources. Additionally, enabling strict Content Security Policy (CSP) headers on internal applications reduces the attack surface by limiting which scripts are allowed to execute, thereby mitigating the likelihood of triggering this specific vulnerability through web-based attacks.