CVE-2026-9921

Description

Uninitialized Use in WebGL in Google Chrome on Android prior to 148.0.7778.216 allowed a remote attacker to leak cross-origin information via a crafted HTML page. (Chromium security severity: High)

CVSS Details

CVSS Score

4.3

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Configurations (Affected Products)

No configuration data available.

Google Chrome on Android < 148.0.7778.216

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

<!--
PoC Concept for CVE-2026-9921
This PoC demonstrates the potential trigger for WebGL uninitialized memory usage.
Note: Actual exploitation requires specific heap grooming and memory layout techniques.
-->
<!DOCTYPE html>
<html>
<head>
    <title>CVE-2026-9921 WebGL PoC</title>
</head>
<body>
    <h1>WebGL Uninitialized Memory Use PoC</h1>
    <canvas id="glCanvas" width="640" height="480"></canvas>
    <script>
        const canvas = document.getElementById('glCanvas');
        const gl = canvas.getContext('webgl');

        if (!gl) {
            console.error('WebGL not supported');
        } else {
            console.log('WebGL context initialized');
            
            // Attempt to trigger the uninitialized use condition
            // by manipulating buffers in a specific sequence.
            const buffer = gl.createBuffer();
            gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
            
            // Hypothetical trigger: Writing/Reading without proper initialization
            // This is a conceptual representation.
            try {
                // In a real exploit, specific shader code and buffer operations
                // would be used to leak memory content.
                gl.bufferData(gl.ARRAY_BUFFER, 1024, gl.DYNAMIC_DRAW);
                
                // Simulate reading back data that might be uninitialized
                const view = new Uint8Array(1024);
                // gl.getBufferSubData(...) would be used in exploitation
                
                console.log('Potential trigger executed. Check memory debugger for leaked data.');
            } catch (e) {
                console.log('Exception:', e);
            }
        }
    </script>
</body>
</html>

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-9921
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-9921
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-9921/
[4] VulDB https://vuldb.com/cve/CVE-2026-9921
[5] https://chromereleases.googleblog.com/2026/05/stable-channel-update-for-desktop_0877304591.html
[6] https://issues.chromium.org/issues/500150338

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-9921", "sourceIdentifier": "[email protected]", "published": "2026-05-28T23:16:50.200", "lastModified": "2026-05-29T18:17:15.137", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Uninitialized Use in WebGL in Google Chrome on Android prior to 148.0.7778.216 allowed a remote attacker to leak cross-origin information via a crafted HTML page. (Chromium security severity: High)"}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-457"}]}], "references": [{"url": "https://chromereleases.googleblog.com/2026/05/stable-channel-update-for-desktop_0877304591.html", "source": "[email protected]"}, {"url": "https://issues.chromium.org/issues/500150338", "source": "[email protected]"}]}}