The _dbus_header_byteswap function in dbus-marshal-header.c in D-Bus (aka DBus) 1.2.x before 1.2.28, 1.4.x before 1.4.12, and 1.5.x before 1.5.4 does not properly handle a non-native byte order, which allows local users to cause a denial of service (connection loss), obtain potentially sensitive information, or conduct unspecified state-modification attacks via crafted messages.