CVE-2025-48828: 
VBulletin vulnerability analysis and mitigation

CVE-2025-48828 is a critical vulnerability affecting vBulletin, a widely used commercial forum software package. The vulnerability allows attackers to execute arbitrary PHP code by abusing Template Conditionals in the template engine. This security flaw was discovered in May 2025 and affects vBulletin versions 5.x and 6.x up to version 6.0.3. The vulnerability was publicly disclosed on May 23, 2025, and was officially assigned a CVE identifier on May 27, 2025 (Karma Security, KEVIntel).

The vulnerability stems from two key issues: first, the ability to invoke protected API controller methods due to PHP 8.1's changes in ReflectionMethod behavior, and second, the ability to bypass template engine security checks. Attackers can exploit this by crafting template code using alternative PHP function invocation syntax, such as 'var_dump'('test'), which bypasses the built-in security checks. The vulnerability has received a CVSS v3.1 base score of 9.0 (Critical) with the vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H, indicating its severe impact (KEVIntel).

The vulnerability allows unauthenticated attackers to achieve Remote Code Execution (RCE) on affected vBulletin installations. This means attackers can execute arbitrary PHP code on the target server, potentially leading to complete system compromise. The vulnerability affects multiple versions of vBulletin, including versions 5.1.0, 5.7.5, 6.0.1, and 6.0.3 running on PHP 8.1 or later (Karma Security).

The vulnerability is believed to be fixed in vBulletin version 6.0.4 and later releases. Organizations running affected versions should upgrade to the latest version immediately. The 'protected method invocation vulnerability' component is reportedly addressed in version 6.0.4 (Karma Security).