CVE-2016-9403: Mybb Merge System

Critical severity, CVSS 9.8. EPSS: 2.6% chance of exploitation in the next 30 days.

newreply.php in MyBB (aka MyBulletinBoard) before 1.8.7 and MyBB Merge System before 1.8.7 allows remote attackers to have unspecified impact by leveraging a missing permission check.

Affected products

• Mybb Merge System: up to and including 1.8.6
• Mybb Mybb: up to and including 1.8.6

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