Description

Privilege escalation due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox ESR 115.41 and Firefox ESR 140.16.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-15T13:16:50.887Z",
  "pubdate": "2026-09-15T13:16:50.887Z",
  "executiveSummary": "A privilege escalation vulnerability has been identified within the graphics component of the Firefox web browser, specifically related to incorrect handling of boundary conditions. This flaw allows a remote attacker to potentially bypass browser security boundaries or escalate privileges on the host system. The vulnerability affects Firefox ESR versions 115.41 and 140.16. The issue primarily resides in how the graphics rendering engine processes data buffers, potentially leading to memory corruption if an attacker successfully triggers an out-of-bounds access. The risk implications are significant, as successful exploitation could lead to arbitrary code execution within the context of the browser process or potentially the host operating system, depending on the sandbox constraints. Exploitation typically requires the victim to visit a malicious website designed to trigger the specific graphics path in question. No specific authentication is required from the user, as the vulnerability is triggered through standard browser rendering processes, making it a critical concern for system security and data integrity.",
  "technicalDetails": "The vulnerability stems from improper boundary checks within the graphics rendering subsystem of Firefox. At its core, the issue is an incorrect implementation of bounds verification when processing graphical data structures or primitives during the rendering pipeline. When the graphics engine receives specially crafted input, it may perform operations on memory buffers without adequately validating the indices or size constraints relative to the allocated buffer memory. This failure in boundary enforcement allows for out-of-bounds (OOB) memory access, which serves as the fundamental primitive for exploitation.\nThe attack flow typically initiates when a user navigates to a web page containing malicious content—such as a crafted SVG, WebGL shader, or accelerated 2D/3D canvas instruction—designed to interact with the vulnerable graphics component. As the browser parses and renders this content, it triggers the flawed function within the graphics subsystem. Because the boundary checks are bypassed, the engine may read from or write to memory addresses outside the intended memory region of the buffer. This OOB read/write capability facilitates the corruption of adjacent memory, which may contain critical object pointers, function table addresses, or control flow metadata.\nAn attacker can leverage this memory corruption to overwrite function pointers or other return addresses, redirecting the execution flow to a malicious payload or returning to a ROP (Return-Oriented Programming) chain. By precisely manipulating the heap layout—often referred to as 'heap spraying' or 'heap grooming'—the attacker can place malicious instructions or data in a predictable location, increasing the probability of successful exploitation. Once the control flow is redirected, the attacker can execute arbitrary code under the security context of the Firefox process.\nThis vulnerability is particularly concerning as it affects the core rendering engine, which must process untrusted web content by default. The lack of strict boundary enforcement in this component invalidates the browser's internal security architecture. If the sandbox is not configured optimally or if a secondary vulnerability is used to escape the sandbox, the attacker could elevate privileges to the level of the user running the browser process, leading to a full system compromise. The vulnerability is present in Firefox ESR versions 115.41 and 140.16, requiring an immediate transition to patched versions to ensure that all graphics-related security checks are strictly enforced and the risk of memory corruption is mitigated."
}