CIVI-SA-2020-09: Privilege Escalation via ACL Smart Groups
In CiviCRM, an Access Control List (ACL) confers limited access to contact records (based on the membership list for a "Group" of contacts). In configurations with "ACL Smart Groups", a flaw allowed limited backend users to re-define their group criteria and gain elevated access. The fix ensures that only trusted users (with permission "edit groups") may re-define the group criteria.