Description

Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-08-18T13:17:31.277Z",
  "pubdate": "2026-08-18T13:17:31.277Z",
  "executiveSummary": "A privilege escalation vulnerability exists within the Graphics: CanvasWebGL component of the Mozilla Firefox browser. The flaw arises from incorrect boundary conditions during memory management and rendering operations within the affected graphics subsystems.\nSuccessful exploitation of this vulnerability allows an attacker to execute arbitrary code or elevate privileges within the context of the application, potentially leading to sandbox escape or complete system compromise depending on the execution context and underlying operating system permissions.\nThe affected products include Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1.\nRisk implications are high, as web-based exploitation vectors can be weaponized via malicious web pages containing crafted WebGL content designed to trigger the out-of-bounds memory access.\nAttacker capabilities require the delivery of malicious content to a targeted user, typically through a compromised or attacker-controlled website that forces the rendering engine to process malformed canvas operations.\nExploitation requirements include convincing a user to visit a malicious URL or interact with compromised web content utilizing the vulnerable Graphics: CanvasWebGL component.",
  "technicalDetails": "The vulnerability resides in the Graphics: CanvasWebGL component, specifically within the handling of memory boundary conditions during graphics buffer allocation, state management, or vertex and pixel data processing.\nThe root cause is a failure to properly validate bounds and size constraints when processing input parameters or rendering commands within the WebGL graphics pipeline.\nIncorrect boundary conditions allow an attacker to trigger out-of-bounds memory reads or writes, leading to memory corruption vulnerabilities such as heap buffer overflows or type confusion within the rendering process.\nThe attack flow begins when a user navigates to a malicious web page designed to interact with the CanvasWebGL API. The web page provides specially crafted input parameters, shaders, or buffer sizes that violate expected boundary conditions.\nUpon processing these malformed inputs, the Graphics: CanvasWebGL component fails to perform adequate bounds checking, resulting in memory corruption.\nAn attacker can leverage this memory corruption to overwrite adjacent critical data structures, function pointers, or control flow data within the browser's memory space.\nBy achieving arbitrary read and write primitives through memory corruption, an attacker can execute malicious payload behavior, bypass security controls, and achieve privilege escalation within the browser architecture.\nThe vulnerability affects Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1.\nAuthentication requirements are none from the perspective of the application layer, as the attack is triggered remotely via web content. Privilege requirements are low, requiring only standard user interaction to visit a malicious web page.\nNetwork exposure is inherent to web browsers, as the attack surface is exposed to any remote content rendered by the browser engine.\nPost-exploitation impact includes arbitrary code execution within the browser's process space, potential sandbox escape, and compromise of the underlying user session."
}