Description
MyBB 1.8.40 does not restrict which usergroup a limited Admin Control Panel user may assign when creating or editing users; the user module offers the Administrators group (gid 4) and its datahandler's verify_usergroup() unconditionally returns true. An admin holding only the delegated user-management permission can assign the Administrators group to an account and escalate to the full Administrator permission set.
CVSS breakdown
CVSS 4.0
Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
High
User Interaction
None
Confidentiality (Vulnerable System)
High
Integrity (Vulnerable System)
High
Availability (Vulnerable System)
High
Confidentiality (Subsequent System)
None
Integrity (Subsequent System)
None
Availability (Subsequent System)
None
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected products
- MyBB / MyBB0 – 1.8.40