Lychee is a free, open-source photo-management tool. Prior to 7.6.4, SecurePathController, which serves GET /image/{path}, concatenates the attacker-controlled path with the local storage root and performs a string-prefix check before canonicalizing dot segments. Under the supported non-default configuration with temporary_image_link_enabled enabled, temporary_image_link_when_logged_in disabled, and secure_image_link_enabled disabled, any authenticated user can submit encoded traversal segments that pass the prefix check and are later resolved by filesystem operations. This permits reading fil