CVE-2026-58054 – MyBB – Privilege Escalation from Limited ACP User Management to Administrator

CVE ID :CVE-2026-58054

Published : June 28, 2026, 1:32 a.m. | 2 hours, 12 minutes ago

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.

Severity: 8.6 | HIGH

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