CVE-2015-8976: Mybb Merge System

Medium severity, CVSS 6.1. EPSS: 1% chance of exploitation in the next 30 days.

Cross-site scripting (XSS) vulnerability in MyBB (aka MyBulletinBoard) before 1.6.18 and 1.8.x before 1.8.6 and MyBB Merge System before 1.8.6 might allow remote attackers to inject arbitrary web script or HTML via vectors related to "old upgrade files."

Affected products

• Mybb Merge System: version 1.8.5 only
• Mybb Mybb: up to and including 1.6.17; version 1.8.0 only; version 1.8.1 only; version 1.8.2 only; version 1.8.3 only; version 1.8.4 only; …

Published 2017-01-31. Last modified 2026-06-17.