CVE-2026-5366: Prefect has Git Flag Injection via commit_sha and directories Parameters Leading to Remote Code Execution (RCE)

Prefect versions 3.1.11 through 3.6.24 are vulnerable to remote code execution due to improper handling of user-controlled input in the GitRepository storage class. The commit_sha parameter, which is passed to git commands, lacks validation and does not include a -- separator to distinguish user input from git flags. This allows attackers to inject arbitrary git flags, such as --upload-pack, enabling execution of external programs. Additionally, the directories parameter can be exploited to inject git flags during sparse-checkout operations. These vulnerabilities allow any user with deployment creation permissions to execute arbitrary commands on worker machines, compromising shared work pools in multi-tenant environments.