In GitLab versions prior to 13.2.10, 13.3.7 and 13.4.2, improper authorization checks allow a non-member of a project/group to change the confidentiality attribute of issue via mutation GraphQL query
https://hackerone.com/reports/762271
https://gitlab.com/gitlab-org/gitlab/-/issues/195327
https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-13334.json