Lektor through 3.3.14 and 3.4.0b15 contains an absolute path traversal vulnerability in the admin API on Windows that allows attackers to escape the project directory by supplying drive-letter paths that cleanup_path does not normalise. Attackers can use a malicious web page with cross-site requests or DNS rebinding against the unauthenticated local server to recursively delete directories via deleterecord or write attacker-controlled files via newattachment.