A platform-dependent path pattern matching issue exists in python-tuf's delegation implementation used by ggshield. On Windows, path matching is case-insensitive due to the use of fnmatch.fnmatch, which applies os.path.normcase that lowercases input on Windows but not on POSIX systems. This causes authorization decisions to differ by OS, violating the TUF specification. An attacker controlling a delegation role with a path pattern differing only by case can exploit this on Windows clients to override legitimate delegations. The vulnerability affects ggshield versions >=1.50.3 and <1.51.0_1 and has a medium severity rating with a CVSS score of 4. A fix is available by replacing fnmatch.fnmatch with fnmatch.fnmatchcase to ensure consistent case-sensitive matching across platforms.