The host is installed with Atlassian Bitbucket Server 7.0.0 before 7.6.19, 7.7.0 before 7.17.12, 7.18.0 before 7.21.6, 8.0.0 before 8.0.5, 8.1.0 before 8.1.5, 8.2.0 before 8.2.4, 8.3.0 before 8.3.3 or 8.4.0 before 8.4.2 and is prone to a command injection vulnerability. A flaw is present in the application, which fails to handle issues in environment variables. Successful exploitation allows attackers with permission to control their username to exploit this issue to execute arbitrary code on the system.