Description

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

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-09-29T13:17:44.973Z",
  "pubdate": "2026-09-29T13:17:44.973Z",
  "executiveSummary": "This vulnerability involves the improper handling of uninitialized memory within the WebGPU component of the Firefox browser. The flaw originates from the allocation of memory buffers without explicit zeroing or initialization, allowing for potential data leakage or memory corruption scenarios.\nThe vulnerability affects Firefox versions prior to 157. Successful exploitation could allow a remote attacker to gain access to sensitive information previously stored in memory or, under specific conditions, influence program execution flow.\nThe risk is categorized as critical for browser security, as WebGPU provides a low-level interface to the GPU, making memory safety errors particularly dangerous. Exploitation typically requires the victim to visit a malicious website that triggers the execution of crafted WebGPU shaders or commands. There is no requirement for elevated privileges or local access, as the vulnerability is exposed via the browser's rendering engine. Attackers capable of leveraging this defect could potentially bypass sandbox protections or facilitate cross-origin data exposure, undermining the fundamental security boundary between isolated web processes.",
  "technicalDetails": "The vulnerability resides in the Graphics: WebGPU component of the Firefox browser. The root cause is the failure to perform proper memory sanitization when allocating GPU-accessible buffers or associated state objects. In C++ and system-level memory management, uninitialized memory buffers may contain residues from previous operations, including heap pointers, sensitive user data, or function addresses.\nThe attack flow begins when a malicious web page issues specific WebGPU API calls, such as createBuffer or requestAdapter, to allocate memory that is subsequently mapped or accessed without initialization. By manipulating the size and type of the allocated memory, an attacker can influence which memory regions are assigned to the buffer. If the browser fails to clear these regions before exposing them to the scripting environment, the attacker can use the GPU's read-back capabilities (e.g., via copyBufferToBuffer or readPixels) to retrieve data from the heap.\nFurthermore, the presence of uninitialized memory within the WebGPU context presents a risk of memory corruption. If the engine uses the uninitialized data to perform internal logic—such as determining offset values for subsequent GPU commands—it may lead to out-of-bounds access or arbitrary memory reads/writes. In an exploit scenario, an attacker might fill the heap with specifically crafted data and then trigger the vulnerability to induce the browser to treat this data as valid control structures.\nThis vulnerability affects Firefox versions prior to 157. Because the WebGPU component interfaces directly with hardware-accelerated drivers and kernel-mode memory managers, the impact of such an error is magnified. Exploitation does not require prior authentication, as the attack is delivered via standard web content. The primary impact is the potential for information disclosure of cross-origin state or, in more complex attack chains, the potential for arbitrary code execution if the memory corruption can be translated into a control-flow hijack. The fix implemented in version 157 ensures that all memory allocated for WebGPU structures is zero-initialized or otherwise sanitized before being exposed to the JavaScript layer, effectively neutralizing the potential for leveraging stale data."
}