Advisories

MyBB - Privilege Escalation from Limited ACP User Management to Administrator

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severity
high
date
Affecting
  • MyBB <= 1.8.40

CWE
  • CWE-269 Improper Privilege Management
CVSS
8.6
CVSS V4 Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Credit
ashdfrkl
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.

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