vBulletin - Authentication Bypass (CVE-2025-48827)

CVE-2025-48827 is a serious vulnerability in vBulletin versions 5.0.0 through 5.7.5 and 6.0.0 through 6.0.3 running on PHP 8.1 or later, allowing unauthenticated attackers to invoke protected API controller methods. This flaw can be exploited remotely, potentially leading to unauthorized access or manipulation of sensitive forum functions, as observed in active attacks in May 2025.

CrowdSec has been tracking this vulnerability and its exploits since 16th of July 2025.

Insights from the CrowdSec network reveal that the attackers trying to exploit CVE-2025-48827 are composed of a fairly even mix of opportunistic and targeted actors. Some attackers employ preliminary reconnaissance, while others use indiscriminate scanning. Data from the CrowdSec community also indicates a gradual decrease in attacks targeting CVE-2025-48827. While still present in the wild, exploitation levels have dropped noticeably week-over-week. This may signal that the vulnerability is becoming less relevant or that defenses are improving fast enough for attackers to lose interest.

Attackers exploit this vulnerability by sending POST requests to the /ajax/api/ad/wrapAdTemplate endpoint, bypassing authentication to invoke protected methods and potentially execute arbitrary system commands.