dbus as used in DBusServer, allows cookie spoofing because of symlink mishandling in the reference implementation of DBUS_COOKIE_SHA1 in the libdbus library. A malicious client with write access to its own home directory could manipulate a ~/.dbus-keyrings symlink to cause a DBusServer with a different uid to read and write in unintended locations. In the worst case, this could result in the DBusServer reusing a cookie that is known to the malicious client, and treating that cookie as evidence that a subsequent client connection came from an attacker-chosen uid, allowing authentication bypass