core/api/user.go in Harbor 1.7.0 through 1.8.2 allows non-admin users to create admin accounts via the POST /api/users API, when Harbor is setup with DB as authentication backend and allow user to do self-registration. Fixed version: v1.7.6 v1.8.3. v.1.9.0. Workaround without applying the fix: configure Harbor to use non-DB authentication backend such as LDAP.
https://github.com/goharbor/harbor/releases/tag/v1.8.3
https://github.com/goharbor/harbor/releases/tag/v1.7.6
https://github.com/goharbor/harbor/compare/v1.8.2...v1.9.0-rc1
https://github.com/goharbor/harbor/commit/b6db8a8a106259ec9a2c48be8a380cb3b37cf517
http://www.vmware.com/security/advisories/VMSA-2019-0015.html