CVE-2026-92011 in Firefox
Summary
by MITRE • 09/15/2026
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, and Firefox ESR 153.3.
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Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability resides within the Graphics: CanvasWebGL component of Mozilla Firefox, representing a critical security flaw that allows for privilege escalation through incorrect boundary conditions. This specific class of error typically involves improper validation or handling of array indices, memory offsets, or loop limits during WebGL rendering operations. When an attacker can trigger these boundary condition failures, they may cause the browser to read from or write to unintended memory locations outside the allocated buffers associated with canvas elements. In modern web browsers, the renderer process operates under restricted permissions compared to the main browser process and user-level applications. However, a successful exploitation of this flaw could allow malicious code running within a webpage to break out of its sandboxed environment, potentially gaining elevated privileges that exceed those intended for untrusted web content.
The technical mechanism behind this vulnerability likely involves insufficient checks on data boundaries during WebGL shader execution or buffer management operations. CanvasWebGL is responsible for rendering 2D and 3D graphics using the OpenGL ES API via software or hardware acceleration backends. If boundary conditions are not strictly enforced, an attacker could craft a malicious webpage that sends specially crafted JavaScript commands to trigger out-of-bounds reads or writes within the GPU driver interface or browser memory space. This misalignment can lead to heap corruption, arbitrary code execution, or information disclosure by accessing sensitive data stored in adjacent memory regions. The severity of this issue is heightened because WebGL is widely supported and frequently used for complex graphical applications, games, and visualizations, increasing the attack surface available to adversaries seeking to exploit browser rendering engines.
From an operational perspective, the impact of this vulnerability extends beyond simple page crashes or denial-of-service scenarios. Privilege escalation in a web browser context can lead to full system compromise if combined with other vulnerabilities or when targeting less hardened environments such as enterprise deployments where browsers run with higher trust levels. Attackers could leverage this flaw to bypass same-origin policies, steal sensitive cookies and session tokens, inject malicious scripts into trusted pages, or establish persistent footholds within the user's environment. The lack of strict boundary checks means that even seemingly benign interactions with WebGL contexts can be weaponized by sophisticated threat actors who understand low-level memory management and browser architecture internals.
To mitigate this risk, users must ensure they are running Firefox version 156, Firefox Extended Support Release (ESR) 115.41, ESR 140.16, or ESR 153.3, as these versions contain the necessary patches to correct the boundary condition handling in CanvasWebGL. Administrators managing enterprise environments should prioritize deploying these updates across all endpoints to prevent potential exploitation campaigns targeting outdated browsers. Additionally, organizations can implement defense-in-depth strategies such as enabling strict Content Security Policies (CSP) to restrict inline scripts and external resource loading, thereby reducing the likelihood of malicious WebGL code execution in the first place. Monitoring browser telemetry for unusual memory usage patterns or crashes related to graphics rendering may also help detect attempted exploitation activities before they result in successful compromise.
This vulnerability aligns with Common Weakness Enumeration (CWE) categories such as CWE-120 Buffer Copy without Checking Size of Input, CWE-787 Out-of-bounds Write, and CWE-788 Out-of-bounds Read, which describe flaws where input data exceeds allocated buffer limits due to inadequate validation. In terms of the MITRE ATT&CK framework, this flaw facilitates techniques related to Initial Access via Web Applications (T1189) and potentially Privilege Escalation through browser exploitation mechanisms that bypass sandbox restrictions. Understanding these mappings helps security teams categorize the threat accurately within their vulnerability management programs and prioritize remediation efforts based on industry-standard risk assessments. Continuous monitoring of vendor advisories and proactive patching remain essential defenses against such low-level memory corruption vulnerabilities in widely deployed software components.