Prefect CVE-2026-7725

The vulnerability exists in the GitRepository class within Prefect's runner storage module, which handles pulling code from remote git repositories. The affected code constructs git sparse-checkout commands by directly concatenating user-supplied commit_sha and directories parameters into command arrays passed to subprocess execution functions. The root cause (CWE-88: Argument Injection) stems from insufficient input validation-attackers can inject git command-line flags (prefixed with -- or -) that are interpreted as options rather than literal directory names or commit references. The patch addresses this by: (1) validating commit_sha against a regex pattern allowing only hexadecimal characters (4-64 chars, supporting SHA-1 and SHA-256), (2) adding a -- argument separator before the directories list to force git to treat all following arguments as positional parameters rather than flags, and (3) issuing a warning if directories contain suspicious double-dash prefixes. This is a classic shell/command-injection pattern where input sanitization bypasses lead to arbitrary option injection in subprocess commands.