Using a "nulled" version of vBulletin refers to using a pirated copy of the forum software where the license verification code has been removed or bypassed
The Risks of Using vBulletin Nulled
If you're caught using vBulletin nulled or experience problems due to its use, you might face: vbulletin nulled
Conclusion
Legal & DMCA Issues: Use of nulled software is a violation of copyright law. vBulletin actively reports piracy, and hosting providers often shut down sites found using unlicensed software. Using a "nulled" version of vBulletin refers to
A modern, mobile-friendly platform for contemporary community discussions. Part 1: What is a “Nulled” Script
To understand the risk, you must first understand the technical definition. vBulletin is commercial software protected by the Internet Brands copyright. When you purchase a legitimate license, you receive the source code along with a unique license number.