Description

Uninitialized memory in the Graphics: WebGPU component. This vulnerability was fixed in Firefox ESR 153.4 and Firefox 157.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-09-29T13:17:45.700Z",
  "pubdate": "2026-09-29T13:17:45.700Z",
  "executiveSummary": "This vulnerability involves an uninitialized memory condition within the Graphics: WebGPU component of the Firefox browser architecture.\nThe flaw stems from improper memory handling, which could potentially allow a malicious actor to access sensitive information previously stored in heap memory.\nAffected products include versions of Firefox prior to 157 and Firefox ESR prior to 153.4.\nSuccessful exploitation could lead to an information disclosure event, where an attacker leverages the reading of stale memory to bypass security primitives, such as Address Space Layout Randomization (ASLR), or to exfiltrate sensitive data.\nExploitation typically requires the user to navigate to a crafted web page containing malicious WebGPU shaders or API calls designed to trigger the uninitialized read.\nThe risk is categorized as significant due to the potential for memory leakage within the browser's sandbox environment, which could facilitate more complex multi-stage attack chains.",
  "technicalDetails": "The vulnerability resides within the WebGPU implementation, specifically concerning how the graphics driver interface allocates and initializes buffers or internal structures before exposure to the WebGPU shading language or API command buffers.\nWhen the WebGPU component allocates memory for graphics-related operations, the system fails to zero-initialize the memory region. If this uninitialized memory is then exposed to the JavaScript context or the GPU process, an attacker can perform an 'out-of-bounds' read or access memory contents that were not properly cleared after their previous use by other browser processes.\nThe attack flow begins when an attacker invokes specific WebGPU API primitives. By sending a sequence of malformed or specifically crafted commands—typically through an HTML5 canvas or WebGPU adapter interface—the attacker forces the browser to allocate memory that contains residual data from past operations.\nBecause the WebGPU component operates within the browser's graphics pipeline, the exposure of this memory can lead to the disclosure of pointers, heap metadata, or temporary data fragments from other tabs or browser subsystems.\nThe lack of initialization acts as an information oracle. If the attacker can map these memory structures, they may be able to discern the memory layout of the browser process, which is a critical precursor to bypassing exploit mitigations like ASLR.\nOnce the memory layout is determined, the attacker may refine their payload to perform further memory corruption, potentially leading to arbitrary code execution if chained with additional vulnerabilities.\nThe scope of this vulnerability is localized to the WebGPU component, affecting both the standard release and the ESR branch of Firefox. Authentication is not required, as the vulnerability is triggered through standard browser interaction with a malicious, web-delivered payload.\nThis issue represents a failure in resource lifecycle management, where the boundary between memory ownership and reuse is not strictly enforced by the browser’s graphics abstraction layer."
}