Gallery before 1.5.9, and 2.x before 2.2.6, does not properly handle ZIP archives containing symbolic links, which allows remote authenticated users to conduct directory traversal attacks and read arbitrary files via vectors related to the archive upload (aka zip upload) functionality.
Gallery before 1.5.9, and 2.x before 2.2.6, does not set the secure flag for the session cookie in an https session, which can cause the cookie to be sent in http requests and make it easier for remote attackers to capture this cookie.