The commit diff rest endpoint in Bitbucket Server and Data Center before 5.16.10 (the fixed version for 5.16.x ), from 6.0.0 before 6.0.10 (the fixed version for 6.0.x), from 6.1.0 before 6.1.8 (the fixed version for 6.1.x), from 6.2.0 before 6.2.6 (the fixed version for 6.2.x), from 6.3.0 before 6.3.5 (the fixed version for 6.3.x), from 6.4.0 before 6.4.3 (the fixed version for 6.4.x), and from 6.5.0 before 6.5.2 (the fixed version for 6.5.x) allows remote attackers who have permission to access a repository, if public access is enabled for a project or repository then attackers are able to exploit this issue anonymously, to read the contents of arbitrary files on the system and execute commands via injecting additional arguments into git commands.
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.