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.

CrowdSec network observations suggest that most exploitation of CVE-2025-48827 involves focused reconnaissance to identify viable targets. Attackers typically tailor their campaigns based on system exposure and configuration. It is unlikely that a given attack is accidental. CrowdSec data also reveals a clear uptick in attacks involving CVE-2025-48827 over the past week. Activity is above the usual baseline, suggesting growing attention from attackers. This may reflect rising awareness, recent exploit releases, or expanded targeting efforts.

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.