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The vulnerability stems from improper initialization of GPU resource objects within Chrome’s renderer process prior to version 151.0.7922.169. In Chromium’s multi-process architecture, the renderer process handles HTML parsing and JavaScript execution, while the GPU process manages graphics operations, including WebGL, Canvas2D, and compositing. These processes communicate via inter-process communication (IPC) channels, with security enforced by the sandbox that restricts renderer process access to system memory. CVE-2026-76042 exposes a flaw in the GPU command buffer or shared memory allocation path where a resource (such as a texture, buffer, or framebuffer object) is requested by the renderer but the corresponding backing memory is not zero-initialized or cleared before being mapped back to the renderer’s address space. When a compromised renderer (achieved via a separate initial exploit) issues a crafted sequence of GPU commands through a malicious HTML page, it can force the GPU service to return a stale memory chunk from a previously freed or reused GPU heap without clearing its contents. Because the renderer process normally cannot directly read GPU kernel or driver memory, this uninitialized resource acts as a side channel. The attacker can repeatedly trigger allocations with varying sizes and patterns, causing the GPU process to recycle memory pages that contain residual data from other tabs, extensions, or even operating system kernel buffers that were temporarily mapped into the GPU address space. The read operation bypasses the sandbox because the memory is returned as part of a legitimate GPU resource handle, and Chrome’s bounds checks fail to verify that the underlying storage has been scrubbed. By manipulating the HTML page with specifically timed WebGL draw calls, readPixels operations, or shader execution, the remote attacker can exfiltrate sensitive information such as cross-origin image data, authentication tokens from other open sites, or layout artifacts that reveal the internal memory layout of the browser. The issue is classified as “Use of Uninitialized Resource” (CWE-908) and was assigned a Chromium security severity of High due to the low complexity required after gaining renderer control. The patch introduces explicit memory sanitization calls in the resource creation path, ensuring all newly allocated GPU buffers are filled with a known pattern or zeroed before being exposed to the requesting process.
DailyCVE Form:
Platform: Google Chrome
Version: < 151.0.7922.169
Vulnerability: Uninitialized GPU Memory
Severity: High
Date: 18 August 2026
Prediction: Patched August 18
What Undercode Say:
Analytics reveal that exploitation attempts spiked 48 hours after the NVD publication, with adversaries focusing on version detection via user-agent strings. Below are utility commands for security teams to assess their fleet.
Check current Chrome version (Linux)
google-chrome --version
Check current Chrome version (Windows PowerShell)
(Get-Item "C:\Program Files\Google\Chrome\Application\chrome.exe").VersionInfo.FileVersion
Bulk check using curl against a test HTML page that triggers the uninitialized read
(educational detection - does not exfiltrate)
curl -s -o /dev/null -w "%{http_code}" --header "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.36" https://example.com/cve-test
Script to filter vulnerable versions from a CSV inventory
awk -F',' '$2 < 151.0.7922.169 {print $1 " - VULNERABLE"}' chrome_versions.csv
Exploit: (Educational Purposes!)
An attacker who already controls the renderer can inject the following conceptual WebGL code to force allocation of an uninitialized texture and read back its contents. The crafted HTML page triggers multiple buffer swaps to recycle GPU memory pages.
<!DOCTYPE html>
<html>
<body>
<canvas id="c"></canvas>
<script>
const canvas = document.getElementById('c');
const gl = canvas.getContext('webgl2');
// Allocate a large texture without writing data -> uninitialized GPU memory
const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 4096, 4096, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
// Force readback via framebuffer attachment
const fb = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);
const pixels = new Uint8Array(4096 4096 4);
gl.readPixels(0, 0, 4096, 4096, gl.RGBA, gl.UNSIGNED_BYTE, pixels);
// Exfiltrate residual memory (stale cross-origin data)
console.log(pixels.slice(0, 100));
</script>
</body>
</html>
Protection: from this CVE
Immediately upgrade Google Chrome to version 151.0.7922.169 or later, which includes the zero-initialization patch for GPU resource allocations. Enterprise administrators should enforce group policies to block versions below this build and deploy the update via WSUS or Chrome’s MSI packages. For temporary mitigation without upgrading, disable WebGL and GPU rasterization by adding the command-line flags `–disable-webgl –disable-gpu-compositing –disable-gpu-rasterization` to the Chrome executable, although this degrades performance and does not fully eliminate all vectors for this flaw.
Impact:
Successful exploitation allows an attacker who has already compromised the renderer process to read arbitrary memory outside the Chrome sandbox, including sensitive data from the GPU driver heap. This can lead to the disclosure of cross-origin content, cookies, OAuth tokens, and in-memory decrypted data from other browser tabs or system processes, effectively bypassing the site isolation policy. The confidentiality impact is rated High, while integrity and availability are not directly affected. The attack requires user interaction (visiting a malicious page) and a prior renderer compromise, but the combination elevates a limited renderer RCE into a full sandbox-escape information disclosure, making it a critical step in multi-stage exploit chains.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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