CVE-2021-39121

Affected versions of Atlassian Jira Server and Data Center allow authenticated remote attackers to enumerate the keys of private Jira projects via an Information Disclosure vulnerability in the /rest/api/latest/projectvalidate/key endpoint. The affected versions are before version 8.5.18, from version 8.6.0 before 8.13.10, and from version 8.14.0 before 8.18.2.

Source: CVE-2021-39121