Copier is a library and CLI app for rendering project templates. In versions 9.5.0 through 9.15.1, the "trust" setting's prefix match ("copier/_settings.py") compares the template URL against a trusted prefix with a raw "str.startswith" and no path normalization, while the URL is normalized when the template is actually fetched ("Path.resolve()" for local paths; libcurl dot-segment removal for "https"). A template reference that textually starts with a trusted prefix but contains ".." is therefore granted trust yet resolves to a different, attacker-controlled template, whose "tasks" / "migrations" / "jinja_extensions" then run without the "--trust" prompt — arbitrary command execution. Version 9.15.2 patches the issue.