CVE-2026-92013 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.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability resides within the Graphics: CanvasWebGL component of Mozilla Firefox, representing a critical class of security flaws known as privilege escalation via incorrect boundary conditions. This specific defect allows an attacker to bypass intended access controls by manipulating input parameters that exceed expected limits or fail validation checks properly. In the context of WebGL and canvas rendering engines, such boundary errors often stem from improper handling of array indices, buffer sizes, or memory allocation requests during the processing of graphics commands. When these conditions are not strictly enforced, it can lead to out-of-bounds reads or writes, which serve as a vector for escalating privileges beyond what is normally permitted by the browser's sandboxing mechanisms.
From a technical perspective, this flaw likely involves a failure in validating user-supplied data before it is passed to lower-level graphics APIs or memory management routines within the rendering pipeline. WebGL applications frequently interact directly with GPU drivers and system memory through JavaScript bindings. If the boundary checks are insufficient, an attacker can craft malicious web content that triggers these unchecked conditions. This may result in arbitrary code execution within the context of the browser process or potentially escape to a higher privilege level depending on how the underlying engine handles the corrupted state. The severity is heightened by the fact that WebGL is widely used for complex interactive applications, games, and data visualizations, making it a frequent target for exploitation attempts aimed at compromising user systems through compromised websites.
The operational impact of this vulnerability is significant as it undermines the fundamental security model of modern web browsers. By exploiting incorrect boundary conditions in CanvasWebGL, an attacker could potentially execute arbitrary code with elevated privileges on the victim's machine. This capability allows for further lateral movement within a network, installation of persistent malware, or theft of sensitive data stored locally by the browser such as cookies, session tokens, and cached credentials. The ability to escalate privileges effectively neutralizes many of the protective layers designed to isolate web content from the host operating system, thereby exposing users to severe security risks including full system compromise.
This vulnerability aligns with CWE-190, which describes integer overflow or wraparound errors that can lead to buffer overflows and other memory corruption issues, as well as CWE-787, an out-of-bounds write where data is written past the end of a buffer due to improper boundary checks. In terms of adversary tactics, this flaw supports techniques associated with MITRE ATT&CK ID T1059, specifically command and script interpreter abuse, or potentially T1203 for exploitation of client software vulnerabilities. The attack vector typically involves delivering malicious web content via phishing emails or compromised websites that leverage the WebGL component to trigger the boundary condition error during rendering operations.
To mitigate this risk, users must ensure they are running a patched version of Firefox. The vulnerability has been addressed in Firefox 156, as well as in extended support releases including Firefox ESR 115.41, Firefox ESR 140.16, and Firefox ESR 153.3. Organizations should prioritize updating their browser infrastructure to these versions immediately to close the privilege escalation gap. Additionally, implementing strict content security policies can help restrict the execution of untrusted scripts that might attempt to exploit WebGL boundaries. Regular monitoring for unusual network activity or process behavior originating from browser processes can also aid in detecting potential exploitation attempts before significant damage occurs.