Description
Craft CMS is a content management system (CMS). In versions 5.6.0 through 5.9.14, the `actionSavePermissions()` endpoint allows a user with only `viewUsers` permission to remove arbitrary users from all user groups. While `_saveUserGroups()` enforces per-group authorization for additions, it performs no equivalent authorization check for removals, so submitting an empty `groups` value removes all existing group memberships. Version 5.9.15 contains a patch.
References2
Metrics
- CVSS 4.0
-
5.3
MEDIUM
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 16 · as of 13 November 2026
- CWE
- CWE-862
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.