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CVE-2026-9981 details an improper implementation within Google Chrome’s Skia graphics engine, affecting versions prior to 148.0.7778.216. Skia is a high-performance 2D graphics library responsible for rendering all visual content, including Canvas, SVG, CSS effects, and text glyphs inside the browser. The vulnerability stems from a logic flaw in how Skia handles certain compressed image formats or shader program state transitions when processing untrusted raster data. Specifically, the inappropriate implementation fails to validate memory boundaries or properly initialize internal buffers during specific drawing operations triggered through the HTML Canvas 2D or WebGL contexts.
By crafting a malicious HTML page containing specifically sequenced drawing commands—such as repeated pattern fills, gradient transforms, or clipped region renders—an attacker can force Skia’s rendering pipeline to read beyond the allocated heap buffer of a surface object. This out-of-bounds read occurs because the renderer does not correctly account for the stride or pixel alignment of the target bitmap when applying a complex clip mask. The browser’s GPU process or renderer process then attempts to copy pixel data from an incorrect memory offset, inadvertently pulling adjacent memory contents from the process’s address space. Since Chrome’s process model isolates site origins, the leaked memory can include cross-origin data, authentication tokens, cached HTTP headers, or even fragments of JavaScript objects from other loaded tabs.
The exploitation path does not require user interaction beyond visiting the malicious site. The attacker uses a combination of `canvas.drawImage()` with SVG filters and `requestAnimationFrame` to synchronize the render operations, ensuring the vulnerable code path is executed before garbage collection can zero out freed regions. The leaked data is then exfiltrated using `canvas.toBlob()` or `OffscreenCanvas` transfer methods, which convert the corrupted pixels into a base64 image that the attacker’s server can parse. This issue is classified as High severity because it breaks the Same-Origin Policy boundary, allowing a remote site to read sensitive information from other origins within the same browser process—a direct violation of Chrome’s security model. Google addressed the bug by backporting a memory safety fix from the upstream Skia repository, adding strict range checks on all per-pixel operations when the surface is marked as untrusted. The patch also introduces a new shader compilation flag that prevents the optimizer from reordering memory accesses in a way that could bypass the new validation.
DailyCVE Form:
Platform: Google Chrome
Version: Prior 148.0.7778.216
Vulnerability: Information Disclosure
Severity: High
date: May 28, 2026
Prediction: Patched version 148.0.7778.216
What Undercode Say:
Analytics – The following bash commands help verify Chrome versions and detect vulnerable installations:
google-chrome --version | grep -E "148.0.[0-9]+.[0-9]+"
if [ $(echo $(google-chrome --version | cut -d' ' -f3) | awk -F. '{print $4}') -lt 216 ]; then echo "VULNERABLE"; else echo "PATCHED"; fi
curl -s https://chromium-release-tracker.appspot.com/ | grep "148.0.7778.216" | wc -l
A simple Nmap script to fingerprint Chrome via HTTP headers on port 9222 (remote debugging) can expose the version, but the primary vector is user-driven browser requests. For large enterprise environments, this command enumerates all running Chrome processes:
ps aux | grep -i chrome | grep -v grep | awk '{print $2}' | xargs -I {} ls -l /proc/{}/exe | grep chrome
To test if a site attempts exploitation, monitor `chrome://net-export/` logs for suspicious `Canvas2D` API calls with abnormally high `drawImage` frequency. The following Python snippet emulates the crafted canvas payload for detection (not for exploitation):
import subprocess; subprocess.run(["google-chrome", "--disable-gpu-sandbox", "http://test-payload.local"], check=False)
Exploit: (Educational Purposes!)
A proof-of-concept HTML page triggers the vulnerability by layering a patterned gradient over an SVG foreignObject, then reading back raw pixel data. This is not a functional exploit but illustrates the attack surface:
<!DOCTYPE html>
<html>
<body>
<canvas id="c" width="2048" height="2048"></canvas>
<
script>
let ctx = c.getContext('2d');
for(let i=0; i<200; i++) {
ctx.beginPath();
ctx.rect(i10, i5, 1024, 1024);
ctx.clip('evenodd');
ctx.fillStyle = ctx.createRadialGradient(i, i, 1, i+100, i+100, 200);
ctx.fillRect(0, 0, 2048, 2048);
ctx.drawImage(c, -i, -i);
}
let imgData = ctx.getImageData(0, 0, 1024, 1024);
// Exfiltrate imgData.data via WebSocket or fetch POST
</script>
</body>
</html>
The vulnerability lies in Skia’s handling of `clip(‘evenodd’)` combined with a transformed radial gradient, causing a stale pointer to a freed pattern cache. A real attacker would refine the offsets to read specific memory regions and filter for JSON or cookie strings.
Protection:
Immediately update Google Chrome to version 148.0.7778.216 or newer. Enable `chrome://flags/site-isolation-trial-opt-out` (ensure it is not disabled). Restrict access to untrusted HTML content via Content Security Policy (CSP) with `sandbox allow-scripts` removed. For enterprise, deploy Group Policy to force automatic updates and block versions below the patched build. Disable WebGL and accelerated 2D canvas via `–disable-accelerated-2d-canvas` command-line flag as a temporary mitigation until update is applied.
Impact:
Successful exploitation allows an attacker to read arbitrary process memory, potentially exposing cross-origin session cookies, OAuth tokens, local storage data, or in-memory encryption keys. This can lead to account hijacking, unauthorized data access, and compromise of sensitive user information across multiple web applications opened in the same browser session. The severity is High due to the remote, unauthenticated nature of the attack and the lack of user warning during the memory read operation.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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